Bicycle horseshoe lock

The utility model discloses a U-shaped lock used for bicycle comprising a lock shell, a locking ring of a locking nick, a lock gate and a wrench fixed with the locking ring; a cavity which is perpendicular to the lock shell figure is equipped in the wrench and the opening of the cavity is opposite to the lock shell; a spring and a wrench pin are equipped in the cavity in turn; the wrench is also equipped with a vertical hole which is perpendicularly penetrated through the cavity and a button is equipped in the hole; the middle part of the wrench pin is equipped with an incline which is backed on to the spring and matched with the cuneiform incline on the end of the button; the direction of pressing the button is perpendicular to that of wrench movement; the position on the lock shell corresponding to the wrench pin end when the lock is opened is equipped with an anti-error lock pin clamp; the spring acting force when the lock is opened drives the wrench pin to move to the lock shell and extend into the pin clamp; in this way, the error locking phenomenon can be prevented in the lock using process; the button is pressed when the bicycle is locked to make the wrench pin overcome the spring acting force and retract to move from the anti-error lock pin clamp; the operation is simple without any additional part.