The spectral distributions of LED backlight displayer are measured at different color temperatures. Several function expressions are fitted according to the related initial data. The variations of illumination factor, blue light hazard factor and circadian factor with color are studied with the utilization of MATLAB. In the visible range, the blue-light-ratio of LED backlight displayer at different color temperatures is calculated. The result show that illumination factor decreases with the increase of the age and color temperature; blue light hazard factor and circadian factor increase with the increase of color temperature, and decrease with the increase of the age. When the color temperature is 1200 K, the ratio of blue-light-ratio of the displayer to blue-light-ratio of candle is 0.783, and the ratio is 10.294 when the color temperature is 6500 K. The influences of the blue light hazard and non-visual biological effect on young people are relatively large, and the young people should try to reduce color temperature of LED backlight displayer. This research provides theoretical reference for personalized design and color temperature adjustment of LED backlight displayer.