Introduction This study aimed to examine the impact of palliative care on the life quality of adults with advanced cancer. Methods After a comprehensive and regular search using [MeSH] keywords in some important databases, 25 published randomised controlled trials (RCTs) involving 5160 adults with advanced cancer were selected and examined through meta-analysis. Results Analysis of 36 reports in 1-3 months follow-up, and 19 reports in 4-7 months follow-up, showed that compared to usual care (g = 0.25; 95%CI: 0.1 to 0.41), palliative care had a significant impact on quality of life (QOL) (g = 0.1; 95%CI: 0.019 to 0.18) of advanced cancer patients. Also, based on the analysis of 15 reports on outpatients (g = 0.27; 95%CI: 0.04 to 0.4), 10 reports of early (g = 0.27; 95%CI: 0.029 to 0.52), and 8 reports of end-of-life (g = 0.24; 95%CI: 0.06 to 0.47) palliative care in 4-7 months follow-up, a significant impact on life quality was shown. However, in four reports, the impact of palliative care on health related quality of life in >= 10 months follow-up (g = 0.19; 95%CI: -0.03 to 0.42) was not significant. Conclusion Systematic QOL assessment with valid tool in palliative care setting would establish quality assurance and could further develop the application of this pretty new discipline in oncology care worldwide.