With regard to college student drinking water optimization problem, this paper uses integrated comprehensive evaluation method by analytic hierarchy process and grey correlation method to evaluate college student drinking water situation, constructs index system by six kinds of factors and four evaluation objects, uses analytic hierarchy process to determine the weights, uses grey correlation method to determine the order of the choice of college student drinking water plan in order to provide a new method for evaluating multilayer complex system and finally concludes that college students should choose the straight drinking water as daily drinking water ideal solution.