The invention provides a clamping mechanism for an intelligent electric energy meter pass box and a clamping method. According to the clamping mechanism, a left clamping portion and a right clamping portion are respectively arranged in a fork body, and the two clamping portions are respectively provided with a cylinder, a connection rod and a shift fork which are fixed in the fork bodies, the connection rods can be driven to move when the cylinders are in operation, so the pass box is clamped tightly through the shift forks, no relative movement is generated between the cylinders and the fork body, and the shift forks can be independently driven. According to the clamping mechanism, clamping and loosening the intelligent electric energy meter pass box can be realized with high efficiency, stability, high compatibility and high reliability, the clamping success rate of the intelligent electric energy meter pass box can be effectively improved, technical support is provided for stable realization of automatic detection on electric energy meters and stable operation of related systems, the clamping mechanism can be widely applied to other electric power companies, electric energy meter production, enterprise mechanism detection and automation systems in related industrial fields, and the clamping mechanism has excellent application prospects.