A method of generating basic probability assignment(BPA) based on sample difference degree is proposed. The triangle fuzzy number models are established, and the proposed difference degree function is used to calculate the difference between the models and the sample under test to generate the initial BPA. In order to eliminate interference effects, the distance between the evidences is calculated, and conflicts are resolved according to the distance calculated and the threshold. In this way, it can output reasonable BPA under the condition of interference and so on. The iris data classification test shows that the proposed method is simple and practical, and has strong ability of interference elimination.