The utility model relates to a safety permutation lock for a door. In the safety permutation lock for a door, on the basis of the performance of an original built-in lock, the cipher permutation function is provided; the anti-theft performance is improved thereby. The safety permutation lock for a door is composed of a lock head, a lock body, and a connecting member. The safety permutation lock for a door is composed of a lock head has two bolts. When the safety permutation lock for a door is unlocked, a key is inserted into a lock hole, and the key is alignment with the cipher for three times according to the designated direction; a rotary handle is rotated to unlock the big bolt, the key is rotated to unlock the small bolt, and the safety permutation lock for a door is unlocked thereby. The safety permutation lock for a door has high safety, and the safety permutation lock for a door can not be unlocked by a skeleton key or destroying a lock core. The utility model is suitable for institutions, enterprises, and families.