The invention discloses a water purifier and a waterway board of the water purifier. The waterway board of the water purifier comprises a raw water inlet, a waste water outlet, a purified water outlet, a raw water waterway, a first rough filtration water waterway, a refined filtration water inlet waterway, a waste water waterway, a first refined filtration water waterway, a second refined filtration water waterway, a purified water outlet waterway, a first-grade filter element water inlet faucet, a first-grade filter element water outlet faucet, a refined filtration water inlet faucet, a refined filtration filter element waste water faucet, a refined filtration filter element water outlet faucet, a postpositional filter element water inlet faucet and a postpositional filter element water outlet faucet. According to the water purifier and the waterway board of the water purifier, raw water can be filtered by the water purifier, and the structure is compact, thereby avoiding the risk of water leakage at the junction of the water purifier; and in addition, a multi-waterway flow direction design is also adopted, so as to meet the requirements of users for multi-waterway output, such as output of purified water and output of pure water.