The invention relates to a new compound positioning method based on fuzzy theory, belonging to the technical field of vehicle positioning. Based on vehicle cyber physical system technology, the positioning data of three positioning devices in a target vehicle and an adjacent vehicle is used, the error of each positioning technology is optimized by using the fuzzy theory and the positioning contribution of each positioning technology is obtained, and then with the positioning contribution as a weight, the fuzzy weighted calculation is carried out to obtain the composite position of the target vehicle. A Kalman filter of fuzzy variable measurement noise covariance is used to filter a composite position. According to the method, multiple vehicle positioning technologies are fused, two indexes of an outlier rate and an absolute error are constructed to reflect the reliability degree of each positioning technology, the rationality of positioning technology fusion is improved, at the same time, an improved Kalman filter is used to filter a fusion result, and the accuracy of positioning is improved.