The objective of this paper is to clarify the strength property of cement-treated clay subjected to cyclic loading during curing period. In this experiment, a series of unconfined compression tests was conducted in term of the clay type, the cement content and slag content to enhance the strength recovery, the timing and level of cyclic loading. The following conclusions are obtained. 1) No significant strength reduction is observed for cement-treated clay when cyclic loading is introduced during curing period. 2) The deformation modulus during cyclic loading increase 4 times of the specimen without cyclic loading. 3) When cyclic loading is subjected to cement- treated clay at the early stage of curing period (such as 7 curing day), the strength increases with increasing Ground-granulated blast furnace slag content. 4) When cyclic loading is subjected in the last stage of curing period (such as 28 curing day), the strength is almost constant irrespective of cyclic loading.