The invention provides a wet type ball mill discharging detection system and belongs to the field of ball mill wet material detection equipment. The wet type ball mill discharging detection system is characterized by comprising a machine frame (1), a sample sieve (5), a feeding mechanism (3), a flushing mechanism, a drying mechanism (6) and a weighing mechanism (7), wherein the sample sieve (5), the feeding mechanism (3), the flushing mechanism, the drying mechanism (6) and the weighing mechanism (7) are installed on the machine frame (1); the sample sieve (5) is rotationally installed on the central axis in the machine frame (1) through a rotation and turning mechanism (4); the feeding mechanism (3), the flushing mechanism, the drying mechanism (6) and the weighing mechanism (7) are annularly arranged on the periphery of the sample sieve (5); the feeding mechanism (3), the flushing mechanism and the drying mechanism (6) are arranged above the sample sieve (5); and the weighing mechanism (7) is arranged below the sample sieve (5) in a liftable mode. According to the wet type ball mill discharging detection system, discharging detection is conducted on a discharging port of a ball mill, the feeding amount and stone material grinding time of the ball mill can be controlled conveniently in time, and accordingly the phenomenon that the granularity is non-uniform in the working process of the ball mill is improved.