The invention relates to a high-voltage switch operating mechanism, in particular to a signal cylinder and a hydraulic operating mechanism with the signal cylinder. The signal cylinder is adopted in the hydraulic operating mechanism and comprises a cylinder body component and a piston arranged in the cylinder body component. An oil inlet channel is arranged at one end of the cylinder body component. A flow adjusting component is arranged on the oil inlet channel. The side, opposite to a plug, of the piston is provided with a piston rod. The outer circumferential face of the end, away from the piston, of the piston rod and the cylinder body component are in seal fit. A constant high-pressure oil cavity is formed in the side, close to the piston rod, of the piston in the cylinder body component and a work oil cavity is formed in the other side of the piston. In the process of use, moving time of the piston can be adjusted simply by adjusting the flow of the oil inlet channel through the flow adjusting component, stepless accurate adjustment can be conducted on closing and opening time of a circuit breaker, and the problem that an existing signal cylinder is poor in closing and opening time adjusting accuracy of the circuit breaker is solved.