The invention discloses a hydraulic overload protecting device of a 
gas spring energy accumulator with a manual oil pumping function. The hydraulic overload protecting device and a slide block hydraulic 
cushion form a 
closed loop. A 
plunger is driven by a pneumatic proportional pressurizing 
piston to extrude oil liquid in a 
system, so that the pressure of the oil liquid of the slide block hydraulic 
cushion reaches the required 
working pressure value from the initial pressure. When a pressing 
machine is overloaded, a pressure indicator transmits a 
signal to enable an 
electromagnetic valve to act to switch an 
air channel, the proportional pressurizing 
piston drives the 
plunger to quickly move to restore, a pressurizing cavity is communicated with a pressure-releasing cavity, and the oil liquid in the slide block hydraulic 
cushion is quickly released to the 
gas spring energy accumulator. After a pressing 
machine slide block is overloaded to surpass a bottom 
dead centre, the oil liquid of the 
gas spring energy accumulator can be automatically supplemented back into the slide block hydraulic cushion, and the initial working state is quickly restored. Once an overload failure is cleared, the pressing 
machine can immediately normally work again according to a program. The pressing machine with the hydraulic overload protecting device is reliable in work and long in maintenance-free period.