The invention discloses a nonlinear closed loop-based LED control system with adjustable light colors, and belongs to the technical field of LED illumination. The control system consists of a microprocessor, an LED driving controller, cold and warm white-light LED strings, an illumination/color sensor, a luminance sensor, a power supply module and a corresponding control algorithm, wherein the illumination/color sensor and the luminance sensor are used for measuring dual-color LED lamp strings and ambient light signals, and after calculation by the control algorithm in the microprocessor, the LED driving controller is controlled to drive the LED lamp strings to generate accurate adjustable light colors to be output. The invention aims to realize regulation and control of the light colors of the LED illumination system so as to satisfy diversified and higher-demanded illumination requirements; and by automatically substituting the influence factors, such as environment illumination, working temperature, life service aging and the like to the control algorithm, the light color modulation precision is higher and the utilization efficiency of electric energy is greatly improved.