The embodiment of the invention provides a LED dimming method and device, and a computer readable medium. The LED dimming method provided by the embodiment of the invention comprises the steps of: when the duty ratio of an original pulse signal is lower than a set threshold value, generating a modulation pulse signal according to the original pulse signal, outputting the modulation pulse signal, generating a modulation current signal according to an original current value, and outputting the modulation current signal, wherein the duty ratio of the modulation pulse signal is m times of the dutyratio of the original pulse signal, the modulation current signal comprises a modulation current value, the modulation current value is 1/m of the original current value, and m is a positive number larger than 1; and calculating a driving current according to the duty ratio of the pulse modulation signal and the modulation current value, and controlling the LED to work with the driving current. According to the embodiment of the invention, the DC dimming precision of the LED is improved when the duty ratio of the original pulse signal is increased.