Helan Mountains is an important ecological barrier in China, Enhancing the protection of ecological forest ecosystem in Helan Mountains has received great attention. Litter is the main source of soil nutrients, and forest litter and soil microorganisms are of great significance to the study of global climate change, while Difference of microbial community structure in litter decomposition of different forest types in Helan Mountains and the influence of different litter physical and chemical groups on microbial community structure are not fully revealed. In this study, composition and diversity characteristics of microbial communities in litter of Qinghai spruce forest, and Pinus tabulaeformis, and mixed forest of Pinus tabulaeformis and Populus davidiana were studied, sampling routine methods and high throughput sequencing methods were used to reveal difference in chemical composition, microbial community composition and diversity characteristics, and explore impact factors of advantage. Results showed that organic carbon content was the largest in the three kinds of forest litters, total phosphorus, the contents of organic carbon, total nitrogen and total potassium in the litter of Pinus tabulaeformis forest, coniferous and broad-leaved mixed forest and Picea crassifolia forest were the largest, and the differences were significant. The C/N and C/P ratios of the litter of Pinus tabulaeformis forest were significantly higher than those of the other two stands, and the value of N/P ratio of the litter of Picea crassifolia forest was significantly lower than that of the other two stands. There was no significant difference in dominant fungi at phylum level among different stands, but there was significant difference at genus level, and the difference of fungi was greater than that of bacteria. At each classification level, the composition of bacteria and fungi community was as follows:coniferous and broadleaved mixed forest