The D-band MEMS rectangular waveguide iris filter was designed and fabricated. The effects of thicknesses of both metalized layer and iris, and their roughness on the performances of the filter were investigated. The prototypes were fabricated using DRIE method. Several techniques including deep etching, electroplating and bonding were employed for the fabrication of the filter. The MEMS waveguide iris filter with a central frequency of (140?3) GHz, insert loss 0.4-0.7dB, and isolation larger than 18dB has been accomplished for the first time. The test results were in agreement with the simulations.