The present invention discloses a method for controlling detergent dispensing and a laundry machine. The laundry machine comprises a control module and an automatic detergent dispensing device. The automatic detergent dispensing device comprises a light transceiver connected to the control module. The control module of the laundry machine receives a detergent detection information sent by the light transceiver to acquire a detergent concentration, determines an amount dispensed, and controls a dispensing action of the automatic detergent dispensing device. The laundry machine disclosed in the invention has a simple structure, offers a convenient method for controlling detergent dispensing, and can be used for a wide range of applications.