[Objective] Litter is an important part of a forest ecosystem. It is of great significance for scientific regulation of a plantation ecosystem to study effects of litters different in quality on soil microbial community composition in the plantation.[Method] To that end, a three-year litter amendment experiment was carried out in a 7-year-old secondary Cunninghamia lanceolata plantation in Xiayang Forest Farm located in Nanping, Fujian, China. The experiment was designed to have eight treatments amended with litters different in quality, separately. Three years later, soil samples were collected from the treatments for analysis, separately, of variation of soil microbial community composition in each treatment.[Result] Results show:(1) the treatment of amending litter of Eucalyptus robusta, high in quality, was 27%, 35% and 19% higher than the treatment of amending litter of Cunninghamia lanceolata, respectively, in soil total microbial biomass, gram-positive bacterial biomass and gram-negative bacterial biomass, while the treatment of amending litter of Cinnamomum bodinieri low in quality, was 29% and 10% lower, respectively, than the treatment of amending litter of Cunninghamia lanceolate in soil total Phospholipid fatty acid and gram-negative bacterial biomass; (2) The soil fungi/bacteria ratio (0.14) was significantly higher in the treatment of amending litter of Eucalyptus robusta than in all the other treatments, and the Gram-positive/Gram-negative bacteria ratio (1.64) was significantly higher in the treatment of amending litter of Cinnamomum bodinieri than in all the others; (3) Amendment of litters, regardless of quality, had no significant effect on soil pH and soil carbon/nitrogen ratio, and the treatment of amending litter of Phyllostachys heterocycla was the highest in nitrate-N content; and (4) Correlation analysis shows that litter carbon content was positively related to total fatty acid, Gram-positive bacterial biomass, Gram-negative bacterial biomass, fungal biomass, and mycorrhizal fungal biomass. Alkyl carbon was positively related to total fatty acid, Gram-positive and -negative bacteria, bacteria, fungi and fungi/bacteria ratio. Methoxy carbon (N-alkyl C), oxy alkyl carbon(O-alkyl C) and aromatic carbon (Aryl C) was significantly and positively related to Gram-positive/Gram-negative bacteria ratio. Redundancy analysis shows that Alkyl C content was positively related to Gram-negative bacteria (16: 1ω7c, 18: 1ω7c) and fungi (18: 2ω6c, 18: 1ω9). Alkyl C content in the litter had a significant effect on soil microbial community structure.[Conclusion] The difference between the litters in alkyl carbon composition is an important index affecting soil microbial biomass and community composition.