The invention belongs to the technical field of preparation of a rice 
molecular marker, and in particular relates to a 
molecular marker for two rice 
brown planthopper-resistance major genes QBph3 and QBph4 which are simultaneously derived from a pest-resistance 
introgression line IR02W101. The 
molecular marker comprises the following steps: carrying out crossing, self-crossing and 
backcrossing on Zhenshan97, which is an 
herbivore-susceptible variety, and IR02W101 so as to obtain genotypes of various BC1F2 single plants; carrying out 
genetic linkage analysis in accordance with 
brown planthopper-resistance grades of various F2: 3 lines during 
seedling stage; precisely locating a resistance 
gene QBph3 of the IR02W101 between long-arm markers t6 and f3 of the 3rd 
chromosome so as to obtain a co-segregative marker c3-14 as well as closely linked markers q1 and m3; and precisely locating QBph4 between short-arm markers p17 and xc4-27 of the 4th 
chromosome so as to obtain closely linked markers p6, p9, c4-5, xc4-7, HJ16, J417 and IN156. The molecular marker disclosed by the invention can be used for effectively detecting whether the pest-resistance 
introgression line IR02W101 and derived varieties thereof contain the 
major gene site or not.