Abstract: pdr5 and snq2 gene knockout was constructed by overlap PCR, and the effects of pdr5 and snq2 mutations on the accuracy and sensitivity of RNR2 promoter-regulated yeast cell sensors in detecting genotoxic compounds were studied. The yeast cell sensors of wild-type, single-gene mutation of pdr5, single-gene mutation of snq2, and double-gene mutation of pdr5 and snq2 were studied. The cell growth inhibition and the fluorescence induction factor of the yeast cell sensors exposed to a series of concentrations of methyl methanesulfonate(MMS), ethyl methanesulfonate(EMS), cisplatin, 4-nitroquinoline-N-oxide(4NOQ), 5-fluorouracil(5-FU), hydroxyurea, salicylic acid and glucose solution were investigated. The results showed that overlap PCR method could efficiently construct the mutant yeast cell sensor. The accuracy of cell sensors of single-gene mutation of snq2 and double-gene mutation of pdr5 and snq2 were both 100%, higher than that of cell sensors of wild-type and single-gene mutation of pdr5 (87.5%). The yeast cell sensor of double-gene mutation of pdr5 and snq2 showed the highest sensitivity in detecting genotoxicity. This study provides guidance for the construction of high accuracy and sensitivity yeast cell sensor, and foundation for further functional research of yeast cell membrane transporter gene pdr5 and snq2.