The invention relates to a juicer and a juicing method thereof, in particular to an efficient automatic fruit juicer and a juicing method thereof. The efficient automatic fruit juicer comprises a rack, a compression and input device, a compression device, a rotary mashing and residue pushing device and the like. The compression and input device comprises a left-right air cylinder I, a push plate, an L-shaped connecting rod, a spring I, a left-right connecting rod I and an L-shaped baffle. The compression device comprises a shell, a compression barrel, a liquid outlet pipe and a residue discharge plate. The rotary mashing and residue pushing device comprises a crushing head, an annular pushing block, a pushing head, a connecting shaft, a left-right air cylinder II, a motor, a left-right air cylinder III, a left-right air cylinder IV, a plug, a spring II, a coupler, a speed reducer, an L-shaped connecting plate and the like. By means of the efficient automatic fruit juicer and the juicing method thereof, efficient automatic operation is achieved, the original taste and flavor of juice are guaranteed, and the taste is good.