In view of the failure rate of a component in distribution system varying with its working time, this paper puts forward a distribution system reliability indices calculation method considering the elements failure rate changes. Combined with the failure times and working time data of components, reconstructive Weibull distribution is established to fit the component failure rate change process. On this basis, the method presents three types of data structures, namely segment data structure, element data structure and load point data structure to represent the topological structure and parameters of the distribution system. When fault occurs, the distribution system will be divided into four types of areas, namely fault area, forward area, backward area and unaffected area. The distribution system is divided after each element breaks down and then the FMEA table is established. At last, time sequential Monte Carlo simulation is used to calculate the reliability indices, the real-time failure rate is considered during simulation. Taking the IEEE RBTS BUS6 for example, the effectiveness of the proposed method is verified.