[Objectives]  To determine the relative effectiveness of different blue light intensities and exposure periods for protecting peppers and cucumbers from damage by Bemisia tabaci, and thereby provide a scientific basis for the development of insect repellent lamps. [Methods]  The effects of different intensities (1, 2, 6, 8, 10, 20, 30, 70 and 150 lx) of blue light (470 nm) on a B. tabaci population were investigated at different times of day (17:00-18:00, 18:00-19:00, 19:00-20:00, 20:00-21:00 and 21:00-22:00). The number of B. tabaci on cucumber and pepper plants were measured once every 3 days with blue lights turned on from 18:00 to 20:00 every day. [Results]  Exposure to blue light between 17:00 and 22:00 had a significant effect on B. tabaci numbers. The strongest repellent effect (a 50.94% reduction) occurred during the time window from 18:00 to 19:00, followed by the time window from 17:00-18:00 (22.29% reduction). Linear regression indicated a positive relationship between the rate of decline in the B. tabaci population and light intensity (P<0.05), which approximated the fomula: y = 3.029 7x + 12.508 (R² = 0.981). The rate of decline of B. tabaci on peppers reached 85.73% after 10 days of exposure to blue light with no significant difference between the upper and middle leaves (P>0.05). Twelve days exposure of cucumber plants to blue light resulted in a 90.33% decline in B. tabaci numbers. There was a greater decline in B. tabaci numbers on upper than on middle leaves during the early stage of light treatment, but no significant difference after 9 days (P>0.05). [Conclusion]  Blue light is strongly repellent to B. tabaci and can be used to reduce the abundance of this pest on vegetable crops.