By doing research on the materials of the Populus main insect damage between 1986 and 2001 and the experimental materials in the 5 counties/districts between 1996 and 2001 in Suqian，we analyse the effect of temperature，damp,rain and sunshine on clostera anachoretas,micromelalopha troglodyta graesers,apocheima cinerarius,apriona gernara hopes,drosicha corpulentas,botry osphas and so on during their different stages of development and seek to find out their relative regularity，probe into warm humidity composite index K which is relevant to the beginning of pest eclosion,set up the method of weather key element estimate for the loss induced by Drosicha corpulentas；so that we can supply a great help for the prediction and prevention of the Populus Insect Damage.