The utility model discloses a side -wall coring is combination formula cam structure for instrument, it includes fixed plate, rupture board, rotor plate triplex. Driving piece drive rotor plate is rotatory around rotatory round pin, makes the follower change from original direction and continues to release to its vertical direction and along the vertical direction, throws off the rotor plate restraint until the driving piece, then orders about the rupture board and form a contained angle along the fixed pin is rotatory with the vertical direction, then along withdrawing to the opposite direction. This device applies to when getting the core instrument in the pit, can realize creeping into and break two and move the complete independence, the work independently mutually noninterfere.