In this paper，an efficient optimization algorithm based on subset simulation is proposed for solving the resource leveling problem of construction projects with multiple resources. In the resource leveling problem，if the decision variables are chosen to be the scheduled starting time for the involved activities，the logical relationship between the activities may be violated during the implementation of the optimization algorithm. In order to avoid this problem，the interval rate variables are introduced to substitute the scheduled starting time in modeling the resource leveling problem of construction projects with multiple resources so as to simplify the procedures of the proposed optimization algorithm based on subset simulation. As shown in the illustrative example，compared with the widely used genetic algorithm，the proposed optimization algorithm can obtain higher improvement in the stability of achieving the optimal solution.