The invention discloses a closed spiral sieve internally provided with monitoring systems. The closed spiral sieve internally provided with the monitoring systems comprises a unit body and the monitoring systems. A base is arranged at the lower end of the unit body. A plurality of units of the same structure are arranged at the upper end of the base, and the units are arranged in a stepped mode. Each unit comprises a supporting frame and a sieve box arranged on the supporting frame. Spiral shafts are driven by motors to rotate. A baffle is horizontally laid at the upper end of each sieve box.The monitoring systems are arranged on the lower end faces of the baffles. Each monitoring system comprises a monitoring probe and a displayer connected with the monitoring probe in a wired mode, wherein the monitoring probe is mounted at the center of the lower end face of the corresponding baffle, the monitoring probe and the sieve surface of the corresponding sieve box are oppositely arranged in a spaced mode, and the displayer is mounted on the end face of the outer side of the corresponding sieve box. Through the closed design, dust and impurities can be prevented from entering the sieveboxes, and the internal sieving condition can be monitored through the internal monitoring systems.