Terahertz frequency doubling technique is a primary way to obtain terahertz signal source with high performance. A 0.38 THz single stage passive Monolithic Microwave Integrated Circuit(MMIC) quadrupler chip is developed by using linear superposition technique. The four-way phase shift power divider is designed by the cascade of planar ring Balun and orthogonal hybrid network, which makes the suppression of fundamental and other useless harmonics. The first procedure in the design is the electromagnetism simulation of passive structure, then the passive structure is combined with the active structure and jointly simulated for optimization. The conversion gain is below -25 dB in the frequency of 370-410 GHz.