Abstract: A CZT detector based on high intrinsic resistivity CZT (CdZnTe) crystals was developed and tested as a monitor of pulsed γ-ray. The time response and 1.25 MeV γ sensitivity of the CZT detector were investigated on the sub-nanosecond pulsed γ radiation generator and ⁶⁰Co source. The experiment results show that the CZT detector have several attractive characteristics like faster time response, lower dark current and better γ sensitivity compared with Si PIN detector, and it can be applied to the measurement of γ pulse with a low intensity.