There exists an optimal angle magnification to make the optodectronic imaging system and human eye matching optimally, and under this condition the optoelectronic imaging system presents the optimal performance. A new evaluation method, minimum resolvable contrast (MRC) channel width, is proposed based on the physical meaning of MRC which can attain the optimal angle magnification for CCD imaging systems. The expression of MRC channel width is built through viewing experiments of CCD imaging systems. The impact of the change of several system parameters on MRC channel width is also analyzed. Results show that the optimal angle magnification attained from MRC channel width has good consistency with practical application.