该文将面向对象的思想引入人工智能的应用领域之一———专家系统中，用以建立推理机的模型。在深入分析面向对象思想实质的基础上，结合推理机的一般功能，提出一种更符合自然认识方法、具有增量型设计特点的推理机模型。这种模型主要由１１个基类构成，其内部机制合理、易维护、柔性大，可以提高整个专家系统的性能。 This paper introduces object-oriented thinking into one of the application fields of artificial intelligence --- an expert system to establish the model of inference engine. On the basis of deeply analyzing the essence of object-oriented thought, combined with the general function of inference engine, this paper proposes an inference engine model that is more in line with the natural understanding method and has the characteristics of incremental design. This model is mainly composed of 11 base class, its internal mechanism is reasonable, easy to maintain, flexible, can improve the performance of the entire expert system.