The trap characteristics and polarization effect on the trapping behavior in Hf0.5Zr0.5O2 ferroelectric field-effect transistors were analyzed. The current transient that corresponds to the trapping/detrapping of charge carriers was measured and the exact time constant spectra were extracted. In accordance with the different time constants and activation energies as well as the dependence of the trapping behavior on the filling conditions, traps that originated from the oxygen vacancies in the Hf0.5Zr0.5O2 layer and from the Si/SiO2 interface trap states were identified. The detrapping peaks in time constant spectra showed a consistent changing trend with the variation of remanent polarization, confirming that the positive polarization enhanced the trapping of charge carriers injected from channel side to the ferroelectric layer.