Abstract: In the intense pulsed radiation fields, the scintillator is generally used as the converter of the γ-ray or fast neutron signals from the source region in an imaging system. The light output characteristic of the scintillator as well as the light collection efficiency of the optic imaging system to the scintillator is the key parameter for determining the system’s sensitivity and dynamic range. The relative light output of five types of inorganic/plastic scintillators such as YAG∶Ce³⁺, ST401, EJ200, EJ260 and EJ264, was obtained through studying the rule about the output current variation of the scintillator and photon-sensitive instrument in various coupling conditions. The influence of coupling distance on the light collection efficiency of the optic imaging system was also studied. The results indicate that the measured value of the scintillator light output achieves good consistency in conditions of different coupling distances, and the anisotropy of scintillating photon emission must be considered to determine the light collection efficiency of the optic imaging system.