For the purpose of studying the rule of the pupil size variation while the luminance level is changing under the classroom’s lighting condition, the variation values of 3 student’s pupil area that under 5 kinds background luminance affording by three kinds of fluorescent illuminant of different color temperature (2 700 K, 4 000 K, 6 500 K)are measured, with iView X eye tracking and the experiment of the measure system of pupil size under classroom lighting to simulate the classroom lighting.The result shows that, the relationship between pupil area and background luminance is negative exponential function under 3 color temperature fluorescent illuminant；under the classroom lighting condition, the pupil area gets smaller when the background luminance is higher, and is getting stable gradually；under the same background luminance, the pupil area is smaller under the lighting of higher color temperature fluorescent.