A target intention predicting method including a dataset obtaining step and a calculating and map mapping step is provided. A host vehicle positioning dataset of a host vehicle and a plurality of target datasets of a target are obtained. Each of the target datasets corresponds to each of a plurality of time points of a time line, and each of the target datasets includes a target position and a target velocity. The host vehicle positioning dataset is mapped to a map. The target position at the last one of the time points is mapped to the map. An updated velocity of the target is calculated according to the target velocities of the target datasets, and the updated velocity is mapped to the map to predicting a target future position of the target on the map at a future time point according to the updated velocity.