The paper performs mathematical calculations for output circuit' s pulse shape of scintillation detector its. Based on MATLAB the output pulse of scintillation detector, it can be included that if a scintillation detector is of 1 ns transition time, 1 ns discrete transi- tion time,once its scintillation' s light decay Coefficient is more than 3ns,the influence of discrete transition time may neglected. Thorough analysis is given to the relation between the RC time constant of output circuit and pulse shape, which is helpful w...