The effect of three treatments on the quality change and the microorganisms’ kinds and quantities of chestnuts in storage was studied. The results showed that, under the condition of cold storage (0～2 ℃), the proportion of total losses of chestnut packed with gunny-bag having holes plastic bag within is the smallest ; while that of the packed with gunny-bag only is the biggest .The peak period of weight-losing during storage is in the first and second month.The rot chestnuts were caused by many kinds of fungi including Phomopsis sp., Fusicoccum sp, Colletotrichum sp., Mucor sp. et al . Notable changes have taken place on the kinds and quantities of the fungi in different periods. The test of restraining fungi with fungicide and k 1 indicated that cholorothalohi had no effect on the fungi ,while carbendazim and k 1 with higher density had powerful restraining effect on them.