The invention relates to a hydraulic clamping device, and belongs to the field of engineering machinery. A thread at the upper end of a hydraulic top penetrates through a second hole in the middle of a cargo boom, and the cargo boom is fixed to the hydraulic top through a thread between a first nut and the thread at the upper end of the hydraulic top in a connected mode; a bolt penetrates through a hole in a hydraulic top base and a third hole in the middle of a lower base, and the hydraulic top is fixed to the lower base through a thread between the first nut and the bolt in a connected mode; one end of a bracket is fixed to the lower base, and the other end of the bracket is fixed to an upper base; one end of each connection rod is connected with a fourth hole in the cargo boom through a first round key, and the other end of the connection rod is connected with a fifth hole in a first clamping handle or a second clamping handle through a second round key; and each first clamping handle and the corresponding second clamping handle are connected to a sixth hole in the lower base through sixth holes in the middle of the first clamping handle and the second clamping handle with a third round key. Through the hydraulic clamping device, the heavy cargo transport efficiency is improved, and the manual labor burden is relieved.