The invention relates to the field of track traffic, and particularly relates to a visualized detection device of a wheel-rail contact relationship and a detection method thereof. The visualized detection device of the wheel-rail contact relationship comprises a speed measuring unit, a trigger unit, two shooting units, a light source, a processing unit and a marker list, wherein the light source comprises two area light sources; the speed measuring unit, the area light sources, the trigger unit and the shooting units are orderly distributed along the advancing direction of a train; the two area light sources are arranged and respectively located at two sides of a detected steel rail; the two shooting units are arranged and respectively located at the two sides of the detected steel rail; the shooting unit arranged at one side of the tested steel rail is opposite to the area light source at the other side of the detected steel rail; and the marker list comprises a plurality of markers which are orderly distributed inside a detection area along the advancing direction of the train. By adopting the visualized detection device of the wheel-rail contact relationship and the detection method thereof provided by the invention, the outlines of the detected wheel and the steel rail can be clearly captured. Thus, the contact situation can be intuitively reflected.