The invention provides a control method and device for multiple heat sources and an absorption type refrigerating unit. The method comprises the steps that the difference value between the cold water outlet temperature and the cold water target outlet temperature of the absorption type refrigerating unit is obtained; when the difference value is larger than 0, the first refrigerating capacity percentage is obtained through the PID algorithm according to the difference value; when the first refrigerating capacity percentage is smaller than or equal to (a-m)%, a valve corresponding to the heat source A is controlled to be opened, and a valve corresponding to the heat source B is controlled to be closed; when the first refrigerating capacity percentage is larger than (a+m)%, the valve corresponding to the heat source A is controlled to be completely opened, and the valve corresponding to the heat source B is controlled to be opened, wherein m is a preset non-sensible zone value; when the first refrigerating capacity percentage is larger than (a-m)% and smaller than (a+m)%, the valve corresponding to the heat source A and the valve corresponding to the heat source B are kept at the current state; and the calculated amount of a controller is reduced, the adjusting precision is improved, and the cold water outlet temperature can be adjusted to the cold water target outlet temperature as soon as possible.