The invention discloses a quantum efficiency (QE) testing apparatus for a solar cell. The apparatus is composed of a light source, a collecting lens, an integrating sphere, a probe and a QE test platform. The integrating sphere has an integrating sphere light outlet. The probe is an arc probe bar, wherein the central angle corresponding to the arc is smaller than 360 degrees. When the probe bar is installed at the integrating sphere light outlet, light from the integrating sphere light outlet is located inside the arc probe bar in an encircling manner. And the circle where the arc probe bar is located is overlaid with the circle where the integrating sphere light outlet is located; or the diameter difference of the two circles is smaller than 5mm and the distance of the centers of the two circles is smaller than 5mm. Using the testing apparatus provided by the invention, reflectivity and QE/IQE testing can be completed during the whole course after the one-off loading operation, so that the testing efficiency and the working efficiency are improved substantially.