Abstract: 5G channel state information (CSI) has rich feature information, but it is greatly affected by environmental information , which directly affects the fingerprint positioning performance. In order to analyze the degree of influence of different factors on 5G signal quality and positioning performance, this paper first expounds the 5G signal characteristics and positioning algorithm based on support vector regression (SVR), analyzes the influence of terminal height, direction, human body occlusion and other factors on signal quality during data acquisition, and tests the positioning performance in three scenarios: hallway, small office and medium-sized conference room. The results show that the 5G signal is greatly affected by the surrounding environment, and the positioning accuracy of the location fingerprint localization algorithm based on 5G channel state information has positioning accuracy of 0.93 m, 1.46 m and 1.94 m respectively in three scenarios, which can meet the needs of most indoor positioning applications.