Prefilter of water purifier

The invention provides a prefilter of a water purifier. The prefilter comprises a shell. An inlet and an outlet are formed in the shell. A barrel-shaped filter net is arranged in the shell, a filter cavity is formed between the outer wall of the barrel-shaped filter net and the inner wall of the shell, the filter cavity is communicated with the inlet, and an inner cavity of the barrel-shaped filter cavity is communicated with the outlet. The prefilter further comprises a scraper bar arranged in the filter cavity and driven by a motor to rotate in the circumferential direction of the filter cavity to scrape-wash the outer wall of the barrel-shaped filter net. A drain outlet communicated with the filter cavity is formed in the bottom of the shell, and an electronic control drain valve is arranged on the drain outlet. The prefilter has the advantages that automatic scrape-washing and automatic flushing are intermittently controlled according to the local water quality and the use filter time, the flushing effici