The utility model relates to a novel mechanism of group is protected to third grade. Current third grade is protected group's trigger and is constructed inconvenient the observation, and relief valve release liquid can't be retrieved. For this reason, this novel mechanism of group is protected to third grade includes that the group is protected to the one -level, the second grade protects the group and the group is protected to the third grade, and the three is articulated in order to respectively by one -level pneumatic cylinder, second grade pneumatic cylinder and tertiary hydraulic cylinder drive, its characterized in that: after a check valve and a spherical stop valve are established ties in turn, together concatenate and return between the liquid pipe at one -level pneumatic cylinder time liquid pipe and tertiary pneumatic cylinder, the one -level is protected group, second grade and is protected group and third grade and protect and be equipped with the fluorescent screen on group's medial surface respectively, and the release mouth of above -mentioned relief valve all returns the liquid pipeline with the owner of adapted support and communicates with each other. This novel mechanism of group is protected to third grade has design science, convenient operation, controls simple advantage, is fit for the supporting use of super great mining height hydraulic support.