The invention provides an LED light source exposure device. The LED light source exposure device comprises an LED light source, a transmitting plate and a press device, wherein the LED light source isarranged at one side of the transmitting plate, a micro-molecule light guide plate is movably arranged at the bottom of the transmitting plate, a conical prism is arranged at an upper end of the micro-molecular light guide plate, an original film and a light-sensitive plate are sequentially arranged at the top of the transmitting plate from bottom to top, the press device is arranged at an upperend of the light-sensitive plate, guide posts are arranged at two ends of the top of the transmitting plate, the guide posts penetrate through the press device, first electromagnets are arranged at lower ends of the guide posts, second electromagnets are arranged at upper ends of the guide posts, and iron blocks are arranged on the press device and are corresponding to the first electromagnets andthe second electromagnets. A few LED light sources are utilized, high exposure quality is achieved, and energy consumption is low.