The invention discloses a Chinese question answering system based on concept, which mainly comprises a data server, a question pre-treatment module, a candidate question set extracting module and a question sentence similarity calculation module. The invention aims at providing a question answering system which is based on concept, can carry out synonym expansion of keywords which are processed by question sentences which are input by the user, understand question sentences better, carry out searching and improve the recall ratio of the question answering system. Furthermore, the system has a Chinese sentence similarity calculation method based on concept from three aspects: word form, word order and word length, and improves searching precision ratio. Meanwhile, the system adopts a high-efficiency retrieval technology to realize rapid extraction of candidate question set, calculates question sentence similarity, sorts question set quickly and returns the sorted questions and answers to the user. The question answering system of the invention gives more precise understanding in concept to the question sentences input by the user and searches the accurate answers. Experiments show that the question answering system of the invention achieves high recall ratio and precision ratio.