Heat shock proteins(HSP)play important roles in coping with environmental stresses and self-protection in animals.Our previous study has demonstrated that the treatment of imidazole derivative KK-42 can increase the survival rate of Litopenaeus vannamei.In order to research the possible molecular mechanism of KK-42 effect on L.vannamei,a part of HSP90 mRNA sequence was first cloned; the spatial and temporal expressions of HSP90 and HSP70 as well as the effect of KK-42 on the expressions were determined.The shrimps(L.vannamei),3.5-5.0 cm long,were soaked for 1 min in KK-42 solution at a concentration of 1.95×10^-4 mol/L or in the solution without KK-42,and then cultured in normal way.Results showed that HSP90 and HSP70 were expressed in mandibular organ,eyestalk,muscle and hepatopancreas tissues,of which the levels from hepatopancreas were higher.Compared to treatment group,hepatopancreas HSP90 and HSP70 mRNA levels were relatively lower although the obvious fluctuations of the levels were found during experiment in control group.Administration of KK-42 could significantly induce hepatopancreas HSP90 and HSP70 expressions.The HSP70 and HSP90 mRNA contents increased by 243.4%,141.3%,410.5% and 121.6%,505.5%,481.7%,respectively,compared with the corresponding controls on day 1,day 2 and day 3 after KK-42 treatment.Our present study demonstrates that KK42 treatment significantly induces the transcriptions of HSP90 and HSP70 from hepatopancreas,which is likely one of the mechanisms of promoting-survival effect of KK-42 on L.vannamei.