A washing machine and a control method thereof are provided. A washing machine includes: a water holding barrel (100); a circulation filtration pipeline, of which a water inlet end and a water outlet end of the circulation filtration pipeline are respectively connected with the water holding barrel (100); a filter device (600), arranged in the circulation filtration pipeline, and having a water inlet (6101), a filtered water outlet (6102) and a sewage outlet (6103); a sewage pipeline (240), being used for receiving sewage discharged from the sewage outlet (6103); a control valve assembly (700), arranged between the water inlet end of the circulation filtration pipeline and the filter device (600). The control valve assembly includes a first valve chamber (711) and a second valve chamber (712) that are independent from each other, and the first valve chamber (711) communicates with the water holding barrel (100) and the water inlet (6101) of the filter device (600), and the second valve chamber (712) communicates with the sewage pipeline (240) and the sewage outlet (6103) of the filter device (600). In a first working state, the control valve assembly (700) is connected with the water holding barrel (100) and the water inlet (6101), and disconnected from the sewage outlet (6103) and the sewage pipeline (240); in a second working state, the control valve assembly is disconnected from the water holding barrel (100) and the water inlet (6101), and connected with the sewage outlet (6103) and the sewage pipeline (240). The control valve assembly (700) can control the two independent waterways at the same time, so the structure is simple and the costs are reduced.