Abstract: ObjectiveTo examine genetic resistance to cypermethrin in Blattella germanica.MethodsSixty anti-cypermethrin resistant strains of Blattella germanica resistant to cypermethrin were included in the study.Biological determination method and a series of cross,backcross and self-bred assays were adopted to test the inheritance of the resistance in the Blattella germanica.ResultsThe resistance indexes of hybrid strain of resistant PX sensitive(RS),sensitive X resistant(SR)were 2.356 and 2.429,with the dominance resistance D values of 0.236 and 0.279,both within the range of 0-1.The backcross(RS×SS)offspring and inbred(RS×RS)offspring F2 tests showed that the ∑χ² were 12.3378 and 37.6869 and all were greater than χ_0.05²(11.07).ConclusionBlattella germanica resistance to cypermethrin is autosomal incomplete dominant inheritance,and the resistance is controlled by polygenic multiple sites.