The invention discloses a water purifier and a control method thereof. The water purifier comprises a
reverse osmosis filter element and further comprises a first flushing flow path, a second flushing flow path, a concentrated
water discharge flow path and a
backflow flow path, wherein one end of the first flushing flow path is communicated with the concentrated water outlet of the
reverse osmosis filter element, the other end of the first flushing flow path is communicated with the water inlet of the
reverse osmosis filter element, one end of the second flushing flow path is communicated with the concentrated water outlet of the reverse
osmosis filter element, the other end of the second flushing flow path is communicated with the water inlet of the reverse
osmosis filter element, one end of the concentrated
water discharge flow path is communicated with the concentrated water outlet of the reverse
osmosis filter element, the other end of the concentrated
water discharge flow path is used for discharging concentrated water to the outside world, the concentrated water
discharge flow path is provided with a third valve
system for controlling the on-off of the concentrated water
discharge flow path, one end of the
backflow flow path is communicated with the concentrated water outlet of the reverse osmosis filter element, the other end of the
backflow flow path is communicated with the water inlet of the reverse osmosis filter element, and the backflow flow path is provided with a fourth valve
system for controlling the on-off of the backflow flow path. In this way, the water purifier can solve the problem of rapid performance attenuation of a reverse osmosis membrane on the basis of increasing the concentrated
water recovery rate.