Abstract: The time responses of Yb∶YAP and Yb∶YAG scintillators were measured with a picosecond solid laser as excited source. Both ordinary and UV-transmitting photoelectric cells were applied respectively for researching the effect of scintillator emission spectrum on detectors’ time response. The experiment results show that the time attenuation constant of Yb∶YAP scintillator emission is 1.206 ns as measured by ordinary photoelectric cell and 0.428 ns as measured by UV-transmitting photoelectric device, and the time attenuation constant of Yb∶YAG scintillator emission is 0.411 ns as measured by UV-transmitting photoelectric device. The time response is better than that of BaF₂ scintillator. There is definite relationship between the time response of scintillator detector and the scintillator emission spectrum.