Background and aims Soil viral diversity and functions in cold alpine regions are highly dependent on soil nutrient availability. Consequently, we reasoned that soil viral functions may be affected in degraded alpine grasslands due to the low soil nutrients. Methods We determined the distribution, diversity and potential functions of soil DNA viruses in non-degraded, degraded and desertified grasslands in typical alpine areas using meta-viromic and high-throughput sequencing analyses. Results A total of 1847 confirmed viral contigs were detected. The number of specific virus contigs increased in degraded grasslands, and the relative abundances of the families Myoviridae and Siphoviridae increased in low carbon content grasslands (degraded and desertified grasslands). The soils in degraded grasslands harbored 47.5% temperate viruses and enriched auxiliary metabolic genes (AMGs) related to carbon degradation (p < 0.05). The prevalence of functional genes related to glycoside hydrolases and glycosyl transferases were 2.8 to 4.3 times greater in degraded than non-degraded grasslands. Conclusions These findings revealed 1) that soil organic carbon is strongly associated with viral life strategy in degraded grassland; and 2) the occurrence of functional interplay between AMGs and dominant bacteria in alpine ecosystems.