According to the structure of the InP diode, 3-D high frequency simulate software was adopted to create accurate physical model and matching circuits of the diode. Harmonic balance simulation was used to simulate the whole circuits. Based on this type of InP Schottky diode, a 270GHz zero bias detector was designed and measured for the first time in China. The measured responsivity is near 1600 V/W at 260 GHz, as well as 1400 V/W over 260～280GHz typically, which corresponds to typical noise equivalent power level(NEP)of 18 pW/ Hz1/2. The measured and simulated results are highly similar, indicating that this solution has the advantages of accurate, simplified and easily optimized.