The present invention discloses a vessel collision avoiding system and method based on Artificial Potential Field algorithm, the method comprises the following steps: (S1) obtaining a vessel information, at least one obstacle information and a target information; (S2) establishing an Artificial Potential Field (APF) by the vessel information, the at least one obstacle information and the target information, wherein the Artificial Potential Field comprises an attractive field of the target and a repulsive field of the obstacle; (S3) combining the attractive field and the repulsive field to obtain a first resultant force; (S4) Adding an external force to the Artificial Potential Field based on the vessel information or the obstacle information; (S5) combining the first resultant force and the external force to obtain a second resultant force; and (S6) the vessel sails in the direction of the second resultant force to avoid the obstacle.