With the rapid development of modern medical technology, electronic endoscopes are applied to the diagnosis and treatment of diseases in the body, and the accurate measurement of their optical imaging performance is of great significance. This article introduces an improved MTF measurement device and its method based on manual detection of electronic endoscopes. The method uses direct detection of resolution plate imaging contrast comparison values to obtain the modulation transfer function that reflects the imaging ability of the optical system. The entire process is completed using automatic integrated image processing technology, which has become the core and effective main component of the optoelectromechanical integration system. The experimental data and the implementation effect installed on the production line reflect that the qualification rates of the manual inspection visual method and the detection method of this measuring device are 94% and 96%, respectively. The MTF curve of the 7.87~12.5 lp·mm^-1 spatial frequency band is more consistent with the theoretical curve of the designed lens, which verifies the effectiveness of the method proposed in this paper. The use of the production helps to reduce human error and significantly improve production efficiency.