A rugged LCD has to pass the high-temperature environmental test to make sure that the LCD can still work even when the ambient temperature is high.A finite element analysis model of a rugged LCD was established in the paper.A rugged LCD was tested to get the temperature distribution.Based on the comparison of simulation results and practical results, the model was optimized and the precision of the simulation results were guaranteed.The temperatures of LCD and LED backlight board at different ambient temperatures and with different drive currents were simulated.The results show that when the ambient temperature reaches 65 ℃, the drive current should be lowered to 150 mA to make sure that the temperature of the LCD is below the LC clear point and the joint temperature of LED is not higher than the maximum limited value.