The present disclosure discloses a drain assembly, has a downpipe and a sealing plug; the upper end opening of the downpipe is provided with a connecting pipe seat by integral molding and the upper end opening of the connecting pipe seat serves as a sewer outlet; the downpipe and the connecting pipe seat internally share a connector that can move upward or downward; the upper end part of the connector is linked with the sealing plug; the pipe wall of the downpipe is integrally provided with a guide seat at the position corresponding to the lower end part of the connector; the guide seat is communicated with interior of the downpipe. Furthermore, the stay wire component is elastically clamped on the downpipe through a wave spring, therefore, the installation speed is increased and the sealing effect of the connection is ensured.