In water-limited ecosystems, photodegradation is a dominant pathway of carbon (C) turnover. However, the combined effects of spectral composition and litter traits in hyper-arid deserts remain poorly constrained, limiting the accuracy of C flux predictions. In a 637-day field experiment with three representative desert species (Populus euphratica, Alhagi sparsifolia and Karelinia caspia), we applied natural light filters to establish six spectral treatments. Full-spectrum exposure increased litter decomposition by 70%; of the five individual wave-bands, only UV-B (280-315 nm) and blue light (400-500 nm) significantly accelerated mass loss, accounting for 43% and 29% of the full-spectrum effect, respectively. These two wave-bands accelerated C and cellulose loss, whereas green light (500-580 nm) selectively promoted hemicellulose and lignin degradation without affecting total mass. UV-B and blue light also increased specific leaf area (SLA) by 12.9% and 7.0% and elevated litter microbial respiration rate (LMR, 24-h incubation at 25 degrees C, 60% relative humidity) by 54.6% and 40.6%, respectively. Across four spectral regions, initial C content, lignin:N ratio, SLA and LMR were significantly correlated with photodegradation rate, with LMR and lignin content per unit surface area being the strongest predictors of susceptibility. These results highlight the co-regulation of photodegradation by spectral composition and plant traits, advancing mechanistic understanding of C cycling in hyper-arid ecosystems and providing refined parameters for Earth system models changing solar regimes. This study quantified litter photodegradation for three representative Taklimakan plant species under six spectral filters. Results showed that UV-B and blue light are the primary spectral drivers of litter photodegradation, with plant traits (lignin, SLA) jointly governing the carbon-loss rate. (sic)(sic):(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)637(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)3(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)((sic)(sic)Populus euphratica,(sic)(sic)(sic)(sic)(sic)Alhagi sparsifolia(sic)(sic)(sic)(sic)Karelinia caspia), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)6(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic):1) (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)70%, (sic)(sic)(sic)(sic)5(sic)(sic)(sic)(sic)(sic), (sic)(sic)UV-B (280-315 nm)(sic)(sic)(sic)(400-500 nm)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)43%(sic)29%.2) UV-B(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(500-580 nm)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).3) UV-B(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(12.9%(sic)7.0%), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(54.6%(sic)40.6%).4)(sic)4(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(SLA)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(LMR)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).