Disclosed are a method for controlling water circulation and processing in a washing machine and a washing machine. The washing machine comprises a washing machine main body (1) and a water circulation and processing system (2). The water circulation and processing system (2) comprises a flocculation container (5) for flocculating the drained water from the washing machine main body (1), the flocculation container (5) being provided with a water level detection apparatus (4). After water is used by the washing machine for washing laundry, the water circulation and processing system (2) subjects the water to flocculation and then circulates same for re-use, and, according to the amount of detergent dosed, the amount of water intake for washing, and the amount of water processed in each flocculation, calculates the dose of flocculant needed for the water to be processed by the flocculation process this time. The dose of flocculant can be precisely calculated by measuring and calculating the amount of water intake for washing and the amount of water to be processed for each flocculation so as to ensure flocculation effects. Furthermore, by calculating the height of flocculation product after layer separation by means of the flocculant dose, using a water level measurement can entirely separate a clean water layer, such that more water joins the circulation for use, saving more water, and enabling flocculated matter to be prevented from mixing with the circulating clean water, improving flocculation efficiency.