Constant-temperature electric water heater capable of preventing water leakage

A constant-temperature electric water heater preventing water leakage comprises an inner container, an electric heating body, a hot water outlet pipe, a cold water inlet pipe, a blow-off pipe and an electric constant-temperature valve, and the electric constant-temperature valve comprises a valve body, a hot water inlet connector communicated with the valve body, a constant-temperature water outlet connector communicated with the valve body, a cold water pipe communicated with the valve body and a water inlet pipe. Two ends of the water inlet pipe are respectively communicated with the water source and the cold water inlet pipe; the water heater further comprises a one-way check valve, a pressure relief pipe and a safety pressure relief valve, the one-way check valve is arranged on a pipeline where the water inlet pipe is communicated with the cold water inlet pipe, one end of the pressure relief pipe extends into the inner container, and the other end of the pressure relief pipe is provided with the safety p