Safety valve block system of clamping oil cylinder and using method

The invention relates to a safety valve block system of a clamping oil cylinder and a using method.The safety valve block system comprises a reversing valve, a two-way hydraulic lock, a first overflow valve and a second overflow valve, the reversing valve is connected with a main oil way and an oil return way, and two one-way valve assemblies in the two-way hydraulic lock are connected with the reversing valve; one one-way valve assembly in the two-way hydraulic lock is connected with a rod cavity of the hydraulic cylinder through a rod cavity oil way, the other one-way valve assembly in the two-way hydraulic lock is connected with a rodless cavity of the hydraulic cylinder through a rodless cavity oil way, the rod cavity oil way is connected with the leakage oil way through a first bypass oil way, and the first overflow valve is arranged on the first bypass oil way. The rodless cavity oil way is connected with the leakage oil way through a second bypass oil way, and the second overflow valve is arranged on t