Since accidents of reinforced concrete structure occur frequently, it is a key issue to ensure the safety and stability of structures during construction. In this paper, each construction cycle was divided into four stages using discrete time method of freezing to establish the computational model. According to random theory, with the characteristics of reinforced concrete structures during construction, a series of recurrence equation is built by stochastic finite element method during construction. Based on a random analysis of practical engineering, the random response time-varying rule of reinforced concrete structure is obtained during construction. The results show that the construction process of reinforced concrete structure could be simulated well based on perturbation stochastic finite element method .Both the mean and standard deviation of deflection of mid-span could be obtained precisely.