Abstract: By the black light lamp lure and investigation day after day,the population dynamics of Lepidoptera phototactic insects in hill area of lower Taihang Mountain is studied. Experimental results indicate that there are 206 kinds of phototactic insect species belonging to 16 families in this region.The dominant species include Ostrinia nubilalis(Hübner),Heliothis armigera(Hübner),Culcula panterinaria(Bremer et Grey),Maruca testulalis(Geyer).Three types of the population dynamics of phototactic insect species could be identified as sporadic appearance,successive appearance with small amount and successive appearance with great number.It reveals quantitative change of Lepidoptera insects and provides scientific basis for making correct policy of controlling the pests.