The invention discloses a faucet used for a water purifier. The faucet used for the water purifier comprises a faucet body, a platform, a water purification hose and a rotary pipe. The water purification hose is mounted in the faucet body. The platform is provided with a shaft bushing, a rotary disc and a supporting plate. A connecting pipe is arranged on the upper portion of the shaft bushing. The rotary disc is connected with the connecting pipe in a sleeving mode. The supporting plate is provided with a supporting frame. The supporting frame is connected with the platform and is provided with a rotary shaft. The rotary shaft is provided with a limiting disc. The limiting disc is provided with a reset device. A gear disc is arranged at the bottom of the rotary shaft and is provided witha rotary belt. The rotary belt is connected with the rotary disc. The rotary disc is provided with a fixing column. A connecting sleeve is arranged on the lower portion of the faucet body. A connecting frame is arranged in the connecting sleeve. A lifting device is arranged at the bottom of the connecting frame. An installation method of the faucet comprises the following steps of (1) previous preparation, and (2) field installation. By adoption of the faucet used for the water purifier and the installation method of the faucet, the problems that the height of an existing faucet used for a water purifier cannot be adjusted, and the faucet cannot return to the original position after being rotated are solved.