In 1991, we used the chlamydospore of Ustilaginoidae virens (CKe.) Takahashi which past winter under nature condition or kept in a freezing machine to inoculate Successfully paddy rice. It was first demonstrated That the chlamydospore of U. cound be kept under the nature condition of Hai Long and cound become the primary infection agent and that the chlamydospore kept under lower temperature (+4℃) without dryness cound be alive about nine months. Following 1990’s experiment, the 91’experiment demonstrated again that inoculation by spraying suspension of spore was possible, and that the period for inoculation adequate was. All of these result provided new method for researching the resistance of paddy rice varieties and reliance for chemical protection.