The invention discloses a gripper for a grabbing mechanism for light weight building material processing, and belongs to the technical field of building material processing equipment. The grabbing manipulator comprises a support assembly, a gripping assembly, and a telescoping assembly. The support assembly comprises a horizontal frame having two parallel side edges. A plurality of groups of third connecting plates for movable connection to the middle portion of the gripping assembly are correspondingly arranged on the parallel side edges of the horizontal frame. A first connecting plate and a second connecting plate are arranged at two ends of the gripping assembly, respectively. The first connecting plate is connected to the telescoping assembly with one end fixed to the support assembly. Gripping plates for gripping building blocks are connected to the second connecting plate. A group of corresponding gripping plates on the gripping assembly on the parallel side edges of the horizontal frame is capable of rotating around the third connecting plates under the push action of the telescoping assembly to get close to one another for gripping a perform or a building block. The grabbing manipulator gripper is able to transfer building blocks formed through multiple cutting at a time with reduced workload for workers and greatly improved processing efficiency.