Abstract: The method of threshold trait analysis described by Tabashnik was used to estimate realized heritability (h2) of resistance to imidacloprid and the development rate of resistance in Bemisia tabaci Middle-East-Asia-Minor 1(MEAM1) cryptic species in Xinjiang,and the cross-resistance of resistant population to different insecticides was detected.The results showed that under the ordinary selection pressure 30%-50%,compared with the original unselected populations,the resistance of MEAM1 to imidacloprid was developed 28.01 times higher after 8 generations by uninterrupted selection,also,the realized heritability(h2) was 0.429 7.Given that h2 of field population was half of those value at 0.214 9,the risk predicting of resistance of MEAMI to imidacloprid for field population showed that it takes 10-8 generations to achieve 10-fold resistance under the selection pressure of 50%-60%,and take 6-4 generations to get the same resistance under the selection pressure of 70%-90%.The results indicated that a high level of risks in the development of resistance to imidacloprid in MEAM1 cryptic species both in field and laboratory conditions.From this detection of cross-resistance,we found that,a medium to low level of cross-resistance to acetamiprid and thiamethoxam which are the same type of insecticides as imidacloprid was obtained at RR=10.78-fold and 4.75-fold,respectively,and 2-3 folds decrease of susceptibility to spinosad,chlorpyrifos,pyriproxyfen and beta-cypermethrin.And also,very low level or null cross-resistance was observed in the treatment of abamectin,spinetoram and sulfoxaflor.