The invention provides a gas injection type independent double-piston rotary hydraulic cylinder and belongs to the technical field of machinery. Through the gas injection type independent double-piston rotary hydraulic cylinder, the problem that double pistons of a hydraulic cylinder in the prior art cannot move independently is solved. The gas injection type independent double-piston rotary hydraulic cylinder comprises a rotary seat and a cylinder body internally provided with a first oil cavity. The front end of the cylinder body is provided with a first through hole. A first piston capableof moving independently is arranged in the first oil cavity and is provided with a first piston rod penetrating out through the first through hole and extending to the front end of the cylinder body.A second oil cavity located in the rear end of the first oil cavity, and a second through hole running through between the first oil cavity and the second oil cavity are formed in the cylinder body. The first through hole and the second through hole are formed coaxially. The first piston rod is provided with a third through hole in a coaxial-through mode, and the third through hole and the secondthrough hole are coaxial and are equal in diameter. A second piston capable of moving independently is arranged in the second oil cavity and is provided with a second piston rod which penetrates out through the second through hole and the third through hole and extends to the front end of the first piston rod. The second piston rod and the second through hole are in seal sliding fit. The gas injection type independent double-piston rotary hydraulic cylinder has a gas injection function, the two pistons can move independently, and thus reliability of workpiece locating is improved.