A novel wafer level package strategy for RF MEMS is presented in this paper, considering the important issues such as the seal material, RF feedthrough and interconnects method. BCB is chosen for the seal material due to its excellent RF performance. Analytical solutions are presented and applied for RF feedthrough design and optimization. Side-wall CPW interconnect technology, which is a novel interconnect concept, is introduced in RF MEMS packaging instead of conventional via-through method. The RF performance of the overall package is verified by 3D EM simulation software HFSS. The packaging structure keeps good RF performance up to 40 GHz.