The invention relates to an LED light source control method and system for a DLP projector. The method comprises the following steps: obtaining an input signal of the DLP projector, and extracting projection display image data from the input signal; detecting the real-time color parameters of pixels in the image data, and judging whether the real-time color parameters reach preset color parameter threshold values or not; outputting a first control instruction to a DMD chip if the real-time color parameters reach preset color parameter threshold values, and adjusting the DMD chip to an off state; and outputting a second control instruction to turn off the LED light source of the DLP projector. When the DMD chip is enabled to be in the off state and the DMD chip does not need a corresponding LED light source, the LED light source of the DLP projector stops working, thereby achieving a purpose of saving energy. Moreover, after the LED light source of the DLP projector is turned off, the above LED light source does not dissipate heat, and the continuous increasing of the internal temperature of the DLP projector can be alleviated, thereby facilitating the prolonging of the service life of the DLP projector.