The invention relates to a fish catching device for a rotationally moulded yacht. The fish catching device comprises a boat body, a controller, an outer cylinder, a support rod, a first air cylinder, an inner cylinder, a spring, a frame, a column, a linear motor, a moving block, a connecting rod, a second sliding rail, a second sliding block, a folding plate, a net bag, a weight, a rope, a second lamp, a first lamp, a first sliding block, a first sliding rail, a rope wheel, a second motor, a third air cylinder, a waterproof shell, a first motor, a vortex propeller, a support column and a second air cylinder, wherein the first air cylinder is arranged at the right side of the boat body; the support column is arranged under a piston rod of the second air cylinder and is arranged on the outer cylinder; the outer cylinder is arranged outside the inner cylinder; the inner cylinder is arranged at the right side of the boat body; the waterproof shell is arranged at the right side of the outer cylinder; the first motor is arranged in the waterproof shell; an output shaft of the first motor extends out of the waterproof shell and is provided with the vortex propeller; the second air cylinder is arranged in the outer cylinder. The fish catching device disclosed by the invention has the advantage that the fish catching device has a large-area fish catching function.