In order to investigate the effects of different culture substrates on the growth and physiological indexes of Plagiomnium acutum (Lindb.) T. Kop., we selected the optimal culture substrate through experimental design, to provid a new way and idea for propagation and cultivation of P.acutum. In this study, six groups of different substrate treatments were set up using the common forest decomposition grade Ⅱ, Ⅲ and Ⅳ Pinus massoniana fallen wood(W_Ⅱ, W_Ⅲ and W_Ⅳ) and commonly used bryophytes cultivation soil［Granular soil (S_G), Generalpurpose nutrient soil (S_N), Grass charcoal soil (S_C)］ as cultivation substrate. The effects of different substrates on the growth length, growth cover, chlorophyll content, total soluble protein content and total soluble sugar content of P. acutum, and the overall growth condition of P. acutum were studied, and finally its influencing factors were evaluated by Pearson correlation analysis and fuzzy affiliation function. The results showed that: (1) the physicochemical properties of different cultivation substrates were significantly different. The total porosity, waterholding capacity, and total nitrogen contents of the fallen wood substrate (W_Ⅱ, W_Ⅲ, and W_Ⅳ) were significantly higher than those of the granular soil (S_G) and generalpurpose nutrient soil (S_N), while the bulk weight, total phosphorus content, and total potassium content showed the opposite. Except for the total porosity and waterholding porosity was significantly different, the other indexes of the grass charcoal soil substrate (S_C) and fallen wood substrates (W_Ⅱ, W_Ⅲ and W_Ⅳ) were similar. (2) Among the six groups of substrates, the cultivation of fallen wood substrate (W_Ⅱ, W_Ⅲ and W_Ⅳ) could effectively improve the growth and coverage of moss gametophyte, S_C substrate could improve chlorophyll content and photosynthetic capacity of the P. acutum, S_G substrate can improve soluble sugar content and soluble protein content and enhance the plant resistance. By comprehensive evaluation of membership function, W_Ⅳ treatment had the highest comprehensive evaluation score and the best comprehensive growth condition. (3) The total porosity, waterholding pore space, waterholding capacity and total nitrogen content of the substrate were highly significantly and positively correlated with the growth morphological indexes of the moss. The capacitance, total phosphorus content and total potassium content of the substrate were significantly and negatively correlated with the growth morphologic indexes of the moss. Compared with soil substrate, the fallen wood substrate had greater porosity and water holding capacity, which is beneficial to the growth of P. acutum. The comprehensive growth and development of P. acutum was the best in the decomposition grade Ⅳ P. massoniana fallen wood (W_Ⅳ), which could be used as the optimal substrate for cultivation. Increasing the porosity, waterholding capacity and total nitrogen content of the substrate was beneficial to the growth of P. acutum.