The invention discloses a method and a device for vehicle passive keyless entering, starting and locking based on ultra-wide band. The device comprises a vehicular key, a master controller, a door lock sensor, a starting / stopping button, a seat sensor and a vehicular body antenna array, wherein the door lock sensor, the starting / stopping button, the seat sensor and the vehicular body antenna array are all connected with the master controller through a vehicular body circuit. The method includes: using UWB (ultra-wide band) signals to precisely position the vehicular key, detecting the position of the vehicular key and the position information of personnel in the vehicle according to each trigger action of a driver, and using a joint judgment method to control operation of a vehicular door lock, a starting system and an alarming system. In addition, the vehicular key is capable of recording and storing information interested by the driver and vehicular dynamic information. Using the method and the device can better avoid accidents caused by misjudgment of the master controller or misoperation of personnel.