The invention discloses a device for testing a double-sided solar cell. According to the device, an optical beam splitter of the fixed beam splitting ratio is arranged at the position of 45 degrees below an upper light source. When the light passes the beam splitter, a part of light transmits to directly irradiate to the surface of the cell or the component, and the other part of light enters a reflecting mirror of 45 degrees through reflection to irradiate to the back surface of the cell through three reflecting mirrors of 45 degrees. According to the method, the situation of inaccurate single side test result of the cell or the component caused by the interaction of double light sources can be effectively avoided.