The invention provides a GNSS/INS/UWB combination-based indoor and outdoor seamless positioning method. The method comprises the steps of arranging a global navigation satellite system (GNSS), an inertial navigation system (INS) and an ultra-wideband system (UWB) at the position of a to-be-measured point; calculating position information, speed information and attitude information of the to-be-measured point through the INS, and carrying out combined positioning on the to-be-measured point through the GNSS and the INS in an outdoor case to obtain outdoor navigation information of the to-be-measured point; and carrying out combined positioning on the to-be-measured point through the UWB and the INS in an indoor case to obtain indoor navigation information of the to-be-measured point. According to the GNSS/INS/UWB combination-based indoor and outdoor seamless positioning method, a GNSS-INS combined system is used for correcting a GNSS measurement value and an INS accumulation error in anoutdoor environment; and the UWB instead of the GNSS is combined with an INS recursion result indoors, so that the problem of poor signal quality of the indoor GNSS is solved. According to a navigation method of employing two positioning modes, indoor and outdoor seamless positioning can be achieved and an accurate and continuous navigation scheme is provided.