Traveling wave(TW)electrode structure is widely used for it needs less multi-action length between optical carrier and digital modulation and can get rid of contribution capacity's constraints on modulation bandwidth. Based on time domain method,TW electrode on InP/InGaAsP electronic absorption modulator is simulated,analyzed and compared with the fabrication on characteristic impedance Z_c and loss coefficient α. The numeric results calculated by time domain method coincide with measurement well. Characteristic impedance is about 45Ω,and the loss coefficient is less than 4 dB/mm from DC to 20 GHz.