The utility model discloses a rainproof lockpicking-difficult lock for vehicles for solving the problems that the general opening U-shaped lock of the vehicle is easily picked through strong force and easily corrodes. The technical scheme is characterized in that the lock consists of a main lock body and an auxiliary lock body, wherein the main lock body is of a U shape, a lock cylinder is arranged on one straight arm of the main lock body, and the end part of the other straight arm of the main lock body is hinged with the other end of the auxiliary lock body; and the auxiliary lock body is an L-shaped auxiliary lock body or a U-shaped auxiliary lock body, and the non-hinged end of the auxiliary lock body is matched and locked with the lock cylinder. The structure of the lock is improved, on the one hand, a knocking acting point is difficult to find, and on the other hand, a distance between the acting point and a hinged point is shortened, so that the generated moment is greatly reduced under the same acting force, the lockpicking difficulty is increased, and the reliability of the lock is improved; and in addition, a splayed protection cap is arranged to protect the lock cylinder, so that dust and water cannot easily enter the lock cylinder, the lock cylinder is prevented from being difficult to open because the lock cylinder is prematurely corroded, and the service life of the lock is prolonged.