Abstract: Objective To study the DND-DNA and DNA-prote in crosslink sinduced by to luene diisony anate(TDI)in Chinese hamster cells(CHL)for gene toxic investigation.Methods Chinese hamster lung(CHL)cells were treated with various concentrations of TDI(0.64,1.28,2.56 mol/L).The amount of DNA-DNA crosslink(DDC)was mea sured by fluoro spectrophotometry.The DNA-protein crosslink(DPC)was detected with KSDS assay.Results No significant difference of DDCs and DPCs with TDI at 0.64 mol/mL was observed(P>0.05).The percentages of DDCs and DPCs in duced by TDI at 1.28 mol/mL and 2.56 mol/mL were significantly higher than that of the control group(P<0.01).Conclusion Certa in dose of TDI caninduce DNA-prote in crosslink and DNA-DN A crosslink.