An electrostatic-precipitator air cleaner includes a base, a shell, a fan, a barrel, a high-voltage discharge module, a distribution module and a precipitation module. The shell is connected to the base. The fan is connected to an upper portion of the shell. The barrel is connected to the shell above the base. The high-voltage discharge module is connected to the base and inserted in the barrel. The distribution module is connected to the high-voltage discharge module. The precipitation module is inserted in the barrel.