The invention discloses a negative pressure wound therapy system capable of detecting colors of exudates, which comprises an exudate collecting bottle, a negative pressure wound therapy device, a wound suite, a sensor, a color detection/control unit, a storage unit and an alarm device, wherein the exudate collecting bottle is used for collecting wound exudates; the negative pressure wound therapy device is composed of a negative pressure source and a controller; the wound suite is used for filling and closing wounds, and communicated with the exudate collecting bottle by a pipe; the sensor is used for acquiring a color signal or visual signal of an exudate in the exudate collecting bottle; the color detection/control unit is arranged in the controller, and used for calculating a corresponding color of the exudate according to the color signal or visual signal acquired by the sensor, and calculating a corresponding alarm signal according to a preset color-alarm signal table; the storage unit is used for storing wound information, wherein the wound information at least includes calculated color information; and the alarm device is used for alarming according to the alarm signal. The invention can carry out online detection on the colors of the exudates, and then send the alarm signal timely to warn medical care personnel or patients, so that the accidents which can cause serious consequences can be prevented in advance.