A washing basin for washing a roller-type mop, which comprises a basin body having a washing chamber and an drainage chamber located one over the other, and the washing chamber is open upwardly for receiving the roller-type mop to be washed, the washing chamber is connected to an external water source through an inlet electromagnetic valve, the drainage chamber is connected with an external drainpipe through an outlet electromagnetic valve; and a waste filter screen which is provided between the washing chamber and the drainage chamber, and the inlet electromagnetic valve and the outlet electromagnetic valve are controlled via a control circuit.