Based on light radiation hazard algorithm, the analytical basis for light radiation hazard reduction of plus optical apparatus in ocular optical path is formed. The original apparatus concept for comparing is introduced to formulate the concepts and expressions of relative light radiation hazard reduction and absolute light radiation hazard reduction, as well as the conversion between them. With the light limited mechanism of pupils, respective light radiation hazard reduction algorithm of tissues forward and rearward pupil is elicited and practical applications are introduced. By visual application analysis, the increasing rate of scotopic luminous efficiency can evaluate the level of visual lightness, and practical algorithm on the basis of increasing rate of dark luminous efficiency expression is elicited. By source changing analysis, light source color rendering evaluation method can evaluate the level of color vision, and the application standard of rendering index Ra for evaluating color rendering is given. The last part shows that this method can realize the purpose of systematic evaluation.