There are several suppliers we can choose in purchasing equipment。The study of the theory in qualification judging and standard defining for suppliers is the key to choosing a supplier。Based on the instinct fuzzy set and the improvement on it, this paper presents a synthesis judging model of multi-attribute decision-making, which will provide a basis of quantitative analysis for the equipment purchase decision-makers and help them make a right decision，and also can offer some valuable advice on the problem of supplier choosing in the invite public bidding。The application of this theory makes the results of the synthesis judging model of multi-attribute decision-making become more reasonable and scientific. In a word, this paper discusses the problem of the supplier qualification judging based on the theory of the instinct fuzzy set, then gives an example of the supplier choosing, and the results indicate the validity and feasibility of the model.