Abstract: In order to effectively inhibit the formation of N-nitrosopyrrolidine(NPYR),in the simulated nitrosation reaction system in vitro,a single factor test was firstly conducted to study the eight common supercritical extraction spices essential oils(SEO),including pepper essential oil,star anise essential oil,green pepper oil,clove essential oil,rosemary essential oil,black pepper essential oil,angelica flavored ginger oil,amomum essential oil,inhibitory effect on NPYR,and response surface center combination test was used to screen the best ratio of compound spices essential oil(CSEO). The single-factor test results showed that,except for amomum villosum essential oil,the other seven SEOs all had an inhibitory effect on the formation of NPYR,and the inhibition rate had a certain relationship with its added concentration. Among them,rosemary essential oil(15、20.0 mL/L)had the strongest inhibitory effect on NPYR(more than 80%),followed by pepper essential oil(5.0,10.0 mL/L),green pepper oil(0.5 mL/L)and clove essential oil(15.0 mL/L)against NPYR. The inhibition rate could reach more than 68%,the inhibitory effect of angelica flavor ginger oil(10.0 mL/L)and star anise oil(15.0 mL/L)was slightly lower(more than 50%),while the inhibitory rate of black pepper essential oil on NPYR was relatively weak(less than 50%). The CSEO composition with the best NPYR inhibition effect was obtained from the response surface center design test:441.0 μL/L peppercorn essential oil,337.0 μL/L star anise essential oil,17.0 μL/L green pepper oil,14.0 μL/L clove essential oil,and 137.0 μL/L rosemary essential oil,the predicted value of the NPYR inhibition rate was 69.84% from the model optimization,the inhibition rate was 68.40% from the verification test,and the inhibition rate of CSEO against N-nitrosodimethylamine(NDMA)was 66.69%.