Abstract: The paper aims to screen the best formula of the chili seedling substrates. The chili seedling substrates were prepared by mixing the pig-breeding litters from a microbial fermentation bed with coconut coirs, cottonseed hulls, wheat brans, and peats, respectively; subsequently, the water extracts of these substrates were separately detected their effects on chili seed germination and seedling growth to screen the suitable raw materials; finally, the plug-seedling tests were performed to determine the best formula of the chili seedling substrates. The results indicated that: the best raw material was coconut coir and its germination rate could reach up to 85%, and slightly better than contrast (P<0.05); the best substrate formula was litter: coconut coir=3:7 (V/V); the emergence rate and survivor rate could reach up to 95.33% and 88.46%, moreover, the seedling height, root length, leaf number, the stem diameter, fresh weight of whole plant/underground par/ aboveground part were all significantly higher than controls and other treatment groups (P<0.05).