The mycelial growth on substrate W80 + WB20 and R80 + WB20 gave significantly faster mycelial growth rate than that on substrate C80 + WB20 for both sterilized and non-sterilized substrate. For both sterilized and non-sterilized substrates, the mycelial growth on substrates C45 + R45 + WB10 was significantly slower than that on substrate R80 + WB20, and that on the substrates C40 + WS40 + WB20, C30 + WS50 + WB20 were significantly slower than that on substrate WS80 + WB20. The results indicated that addition of cotton seed hull decreased mycelial growth compared to sole rice straw or wheat straw substrate. Compared to the sterilized substrate, the non-sterilized substrate exhibited significantly higher mycelial growth rate.