Abstract: The high computational complexity and large memory requirements will be encountered when the electro- magnetic compatibility and interference （EMC/EMI） problems of electrically large objects are considered using time domain integral equation （TDIE） numerical technique. Plane wave time domain （PWTD） is employed for reducing the computation- al scale of TDIE. The outgoing rays table and incoming rays table strategy are adopted for decreasing the memory require- ments, and a new forward contribution project method are presented. Numerical results that demonstrate the validity and effi- ciency of proposed scheme are presented in this paper.