The present invention relates to a mutual-constraint safety multi-drawer locking mechanism, consisting of a mounting bracket (1) formed by a main bottom plate (4), an upper top plate (5), a lower bottom plate (6), a limit cover plate (7) and a curved baffle plate (8), and a driving mechanism formed by a "L-type" base plate (21), a lock-plate (22), a shaft pin (23) and a compression spring (24), and an action actuating mechanism which formed by an optional-one model including a spindle and several sets of shaft sleeve and a an all-drawer locked model including a lack lever, a fixed lock piece and a sliding lock piece. The length of spindle is the sum of that of assembled shaft sleeve components and the height of tilted surface on one rotary shaft sleeve, so, only one rotary shaft sleeve has the rotary gap, thus only one drawer may be opened each time. When the lock lever controls the lock head to block up the gap, all-drawer may be locked up. Under only one drawer opened conditions, the other drawers shall be never opened, thus it have high applicability.