To address the issue of accurately extracting the amplitude of photoelectron pulses outputted by microchannel plate-based photon-counting imaging detectors, this study investigates the correlation between the synthesis-shaping method parameters and the amplitude accuracy of pulse signals. A quasi-Gaussian synthesis-shaping approach tailored for photoelectron pulse signals is implemented using deconvolution techniques and impulse response invariance methods. The simulation results demonstrate that under a white noise standard deviation of 0.1 in the input signal, the standard deviation of the extracted amplitude converges to 0.02 as the shaping width increases, thereby enhancing the accuracy of pulse amplitude extraction. Furthermore, based on an analysis of the relationship between the pulse recognition threshold, pulse miss rate, and false recognition rate, a comparative analysis of amplitude was conducted on authentic photoelectron pulses outputted by the detector. The synthetic shaping method is closer to the real amplitude distribution than the Sallen-Key shaping method and direct amplitude extraction. This is a novel approach for high-resolution photon counting imaging applications.