The invention discloses an electric energy dehydrator energy-saving hydraulic device and a control method thereof. The device comprises a rack, the rack is equipped with an electric energy dehydrationmodule, a hydraulic drive mechanism includes a main oil tank, auxiliary oil tanks, and a small oil pump and a large oil pump that are connected to the main oil tank, as well as a number of compactionoil cylinders and auxiliary oil cylinders, upper pressure plates are fixed on the compaction oil cylinders, the auxiliary oil cylinders are fixed to the compaction oil cylinders, the auxiliary oil tanks are disposed above the compaction oil cylinders, and are connected to compaction oil cylinder rodless cavities through liquid controlled prefill valves, the large oil pump is connected to compaction oil cylinder rod cavities through a return oil way controlling the return of the compaction oil cylinders, the small oil pump is connected to the auxiliary oil tanks through a first branch controlling the motion of the auxiliary oil cylinders, and the small oil pump is connected to the compaction oil cylinder rodless cavities through a second branch controlling the downward pressing of the compaction oil cylinders. According to the invention, auxiliary air cylinders drive the hydraulic device to press downward to achieve quick pressing, compaction air cylinders can achieve rapid return, three-stage squeezing is employed for treatment, and the dehydration effect is improved.