The tropism of six kinds of stored grain pests,Tribolium castaneum, T.confusum，Sitophilus oryzae，S.zeamais，Liposcelis bostrychophila, L. decolor to yellow and blue was researched under laboratory condition by color correction. The results showed that there were significant differences among most of the trapping effect of yellow and blue to different pests. The trapping effect of yellow only appeared stable to Tribolium castaneum with the highest trapping rate of 19.76%. The significant trapping effect of blue appeared to T.confusum, S. zeamais, L. bostrychophila and S. oryzae as without food source, with the trapping rates 39.9%, 28.6%, 24.6%, 22.6%, respectively;Liposcelis most showed phobotaxis reaction. Food as a background has obvious interfere on the trapping effect. After adding a food source as a background, the trapping rate of yellow to T. castaneum, T.confusum and S. zeamais increased significantly; the increase of trapping effect of blue to T. castaneum was the top one. While to T.conf usum changed from trapping to elude. The results showed that the trapping effect of yellow and blue to stored grain insects was interfered by extraneous factors, which provided ideas for the research and development of equipment for trapping by color and light waves.