The invention discloses an efficient method for detecting impact toughness of polycrystalline diamond compacts, which comprises the following steps of enabling a steel ball to freely fall at the certain height to lead the steel ball to successively punch a fixing point on the edge of the front side of a polycrystalline diamond compact (PDC) testing part provided with a gasket at the back; integrally fixing the gasket and the PDC testing part in a groove which is arranged on a freely-falling body path of the steel ball and in a shape matched with shapes of the gasket and the PDC testing part; and counting times of the steel ball punching through a laser sensing counter to obtain impact power values when visible cracks take place on the surface of the compact or the compact is broken. The method achieves point-to-point contact between the steel ball and a sample, can well simulate an actual forcing state of the PDC materials, can conveniently control frequency of ball falling to control impact frequency to enable the impact frequency to be maintained on the best situation, and adopts the simple laser sensing counter to count the times of impact. The method is simple, low in cost, convenient to use and easy to popularize.