The Square Integral Method based on the Minimum Resolvable Contrast (MRC) is to be introduced in this paper as an evolution for the design and evaluation of optoelectronic imaging systems. It is well known that there exists an optimal angle magnification which can make optoelectronic imaging systems and human eye matching optimally, so that optoelectronic imaging systems can performance best. Based on MRC (Minimum Resolvable Contrast) and channel width, a new method called Square Integral (SQI) method was presented for evaluating the general performance of a CCD imaging system, and attaining the optimal angle magnification or optimal viewing distance. Results calculated with this method are in good agreement with the experimental measurements. From the agreement between the practical use and the theoretical predictions for the variation of CCD size, optical focus, luminance and human vision, it demonstrates that the SQI method is an excellent universal measure for the optimal angle magnification and the performance of CCD imaging systems.