The invention discloses a dimmable LED illumination system with temperature protection function, which comprises an LED array, a voltage converter current-detecting module, an over-voltage and open-circuit protection module, a dimming switch, a current reduction and dimming controller and a temperature sensor. The current reduction and dimming controller receives a working temperature signal of the LED array monitored by the temperature sensor and controls the on and off of the dimming switch; and the dimming switch controls the on and off of the working current of the LED array so as to achieve the effect of controlling the work of the LED array according to the working temperature of the LED array. The dimmable LED illumination system does not cause color offset and has higher adjustingprecision and speed. In addition, the temperature adjusting mode of the LED array provided by the invention is compatible with a current popular digital dimming mode, so the system can be improved based on the primary equipment, and the upgrade cost is reduced.