System detection technology based on multi-sensor information fusion makes full use of redundant and complementary information between sensors, which overcomes the shortcomings of single sensor and improves the detection accuracy. In this paper, the detection technology is briefly introduced, which contains the basic model and detection process of a detection system. According to the different abstract degree of information, the system detection process is divided into three different forms i.e., data level fusion, feature level fusion and decision level fusion. The key technologies about the multi-sensor detection system are analyzed, which include the sensory technology, communication technology and fusion algorithm. Finally, the developing trends of the proposed detection technology are discussed with applications.