The stable front fork lock structure for bicycle includes a hinge shaft, a lock plate and a locking block, wherein the lock plate is a rectangular sheet structure, the lock plate is provided with a long circular hole along the length direction thereof, the hinge shaft penetrates through the long circular hole to be vertically fixed on the front fork cylinder; the locking block is fixed on the other fork cylinder of the front fork, a lock body and a stop plate are fixed on the locking block, the lock body and the stop plate are provided with a through groove which is matched with the thicknessof the lock plate and can accommodate the lock plate; The lock body is internally provided with a lock tongue, the lock tongue is provided with a keyhole, and the keyhole is matched with a key. When the bike needs to be locked, one end of the lock plate is pulled, the other end of the lock plate extends the gap between the front wheel spokes and get into the through groove between the lock body and the stop plate, the lock key is inserted, the locking tongue is ejected out, and get through the long circular hole of the lock plat in the through groove, so that the lock plate is locked, and thepurpose of the lock vehicle is achieved, In addition, because the position between the front fork cylinder and the front wheel is compact, the it is difficult for the stealing person to use the toolto destroy the lock structure, and the safety coefficient of the lock structure is enhanced.