Objective To analyze the relationship between serum microRNA(miR)-204 and miR-200b lev-els and clinical efficacy in patients with oral submucosal fibrosis(OSF).Methods A total of 110 patients with OSF who visited Affiliated Hospital of Hebei Engineering University from December 2021 to December 2022 were collected as the study group,another 50 healthy people who underwent physical examination during the same period were collected as the control group.The quantitative real-time PCR(qRT-PCR)method was ap-plied to detect and compare the serum levels of miR-204 and miR-200b in the study group and the control group.The study group was divided into miR-204 high expression group and low expression group,and miR-200b high expression group and low expression group.The clinical efficacy,transforming growth factor β1(TGF-β1),interleukin-6(IL-6),clinical pathological features,and visual analogue scale(VAS)of patients with different levels of serum miR-204 and miR-200b were compared,and Spearman and Pearson methods were applied to analyze the correlation between serum miR-204 and miR-200b levels and various indicators in the study group.Results The serum level of miR-204 and miR-200b in the study group was obviously lower than those in the control group,and the difference was statistically significant(P＜0.05).The total effective rates of patients in the high expression group of miR-204 and the high expression group of miR-200b were both 100.00％,which were higher than the total effective rates of the low expression group of miR-204 and the low expression group of miR-200b(86.79％and 88.89％)respectively,and the differences were statisti-cally significant(P＜0.05).The results of univariate analysis showed that the serum levels of miR-204 and miR-200b in OSF patients with chewing betel nut,mouth opening degree≤28 mm,oral mucosal lesion area＞4 cm2,and VAS score＞3 points were obviously lower than those with non chewing betel nut,mouth opening degree＞28 mm,oral mucosal lesion area≤4 cm2,and VAS score≤3 points,and the differences were statis-tically significant(P＜0.05).The levels of TGF-β1 and IL-6 in patients with high expression of miR-204 and miR-200b were obviously lower than those in patients with low expression of miR-204 and miR-200b,and the differences were statistically significant(P＜0.05).The correlation analysis results showed that the serum levels of miR-204 and miR-200b in patients with OSF were negatively correlated with oral mucosal lesion are-a,VAS score,TGF-β1,IL-6(P＜0.05),and positively correlated with mouth opening degree(P＜0.05).Conclusion The serum levels of miR-204 and miR-200b in patients with OSF are closely related to clinical ef-ficacy,and when the serum levels of miR-204 and miR-200b increase,OSF patients have better clinical efficacy.