The invention discloses a vehicle-mounted weighing data processing method, comprising the following steps of (1) collecting load data measured by a sensor and performing filter processing; (2) processing the filtered data by adopting a track processing method and ensuring the data stability; (3) judging whether a vehicle is started, if yes, switching a filtering and tracking parameter to a dynamic filtering cut-off frequency and a dynamic tracking speed rate, otherwise switching the filtering and tracking parameter to a static filtering cut-off frequency and a static tracking speed ratio, then repeating the steps (1)-(3). The data processing method is used for eliminating the interference of vehicle factors, road factors and environment factors to the weighing result of a vehicle-mounted weighing system, so the stability and accuracy of the weighing result are ensured.