Drainage device and method capable of utilizing water discharged by washing machine in the third time

The invention discloses a drainage device and method capable of utilizing the water discharged by a washing machine in the third time. A joint short pipe used for draining is connected to a water outlet of the washing machine; a water chamber is arranged at the bottom of the joint short pipe; two joints are arranged on the outer bottom of the water chamber; a solenoid valve is mounted on the first joint and then the first joint is connected to a draining pipe; and a solenoid valve and a water pump are mounted on the second joint and then the second joint is connected to a draining pipe. The solenoid valves corresponding to different washing times are switched on through a controller, so that water is discharged through the draining pipes corresponding to the washing times, and the water discharged in the third time can be completely utilized for mopping and washing the floor, flushing toilets, washing feet, cleaning future, windows and doors, and washing dirt objects. According to the invention, water resources are saved, water expense is saved, and the drainage device is convent to use.