The sky luminance distribution model studied by information methods use a new arithmetic to solve complex optimization heuristic algorithm, ant colony system. Through analyzing and optimizing the effect factors of sky luminance by the ant colony system, the study got the coefficients value of sky relative luminance distribution numerical expressions. Based on the study, develop a set of convenient and practical sky luminance model calculation software, which can provide an intuitive and easy calculation. This model has higher precision. It provides valuable results for day lighting using, especially high precise and standard work of day lighting design both in theory and application.