Abstract: Taking strawberry main cultivar ‘Akihime’ seedlings as test material, 10 composite substrates with different ratios of peat, coir dust and perlite were designed to analyze the effects of different composite on the growth of strawberry seedlings, in order to accurately select the optimal substrate for improving the quality of strawberry seedlings.The results showed that the pH of composite substrates used for strawberry seedling growth ranged from 4.90-7.16,EC value ranged from 0.22 mS·cm^-1 to 0.30 mS·cm^-1,and conductivity ranged from 504 μS·cm^-1 to 686 μS·cm^-1.Compared with other treatments, the growth indexes of strawberry seedlings treated with S9 were better, including survival rate of 81%,plant height of 14.2 cm, number of new leaves 4.6,root length of 13.71 cm, rhizome diameter of 7.15 cm, and new leaves chlorophyll content of 40.17 on the 30^th day after seedling cutting.Meanwhile, the physicochemocal properties of S9 composite substrate were analyzed as follow: the pH was 6.23,the EC value was 0.24 mS·cm^-1,the conductivity was 605 μS·cm^-1,the true density was 95.76 g·cm^-3,the porosity was 7.69%,the void ratio was 22.62%,the liquid phase ratio was 63.20%,the solid phase ratio was 4.23%,the gas phase ratio was 32.56%,and the water-solid ratio was 14.92%.In conclusion, it was recommended that the composite substrate of S9 was more suitable for the growth of strawberry seedling in container.