Abstract: This paper is concerned with an assessment model of air environmental quality by using fuzzy neural network with multi criteria learning algorithm.Regarding the evaluation criterions of air environmental quality as fuzzy sets and using multi output neural network to acquire a actual output vector and taking it as degree of membership of evaluation sample to the fuzzy set,the subjective affect in establishing evaluation index of traditional single output network can be overcome.When take the degree of membership vector as weight value and grade the evaluation sample synthetically to evaluate air environmental quality,we can avoid the difficulty in maximum degree of membership criterion when the component of degree of membership vector is not concetrated.The disadvantage of converging slowly and liable to local minimum when adopting single criterion learning neural network could get over by using multi criterion learning neural network.