In order to reduce the dependence of pedestrian navigation on satellite navigation system and wireless communication, a method is studied to construct pedestrian navigation system based on micro inertial technology and human biological kinematics. In the study, the distributed system structure is arranged on human legs instead of feet, and the key technologies, including conception of virtual inertial sensor, initial alignment and error correction, precise gait-phase detection, effect and inhibition of environmental magnetic field are presented. A detailed analysis of the performance characteristics of the pedestrian navigation system is carried out in the environment with or without electromagnetic interference. Experimental results show that, the prototype of virtual inertial sensors works functionally, and the position error with electromagnetic interference accounts for 2.5% of the walking distance. The key technologies proposed in the study can effectively improve the positioning accuracy of pedestrian navigation system, and independently achieve longer time personal navigation in the GNSS and Wireless communication attenuation or invalid environment.