Objective: To assess the responsiveness of the Chinese 9-item Catquest short-form questionnaire in Chinese patients undergoing cataract surgery, and to establish the minimal clinically important difference (MCID) using anchor-based and distribution-based methods. Methods: This prospective observational cohort study included 213 cataract patients scheduled for surgery at the Eye Hospital of the Wenzhou Medical University after a full ophthalmic examination. Patients who completed the questionnaires and a 7-point Global Impression of Change (GIC) scale as an external anchor in the 1-3 month follow-up period were analyzed. The floor or ceiling effects were examined. A paired t-test was used to compare scores and habitual binocular distance visual acuity (HBVA) over time. The responsiveness of the Catquest-CN was also assessed by effective size (ES), standardized response mean (SRM)and change ratio (CR). Then the patients were divided into groups according to preoperative HBVA, presence of ocular comorbidity and whether surgery was performed on one or both eyes. A one-way ANOVA or independent t test was used to compare the difference of change in scores among the subgroups. The distribution-based methods (1 effective size, 1 standard error of measurement and 1/2 standard deviation of change in scores) and anchorbased methods (linear regression coefficients) were used to estimate MCID. And finally, the MCID was determined by its mean value. Results: Follow-up data were available for144patients. The questionnaire showed minor floor or ceiling effects (2.8%) before surgery, which increased to 17.3% 1-3 months later. The change in scores over time was 11.04±7.91points and for HBVA it was 0.4±0.4.The former showed a significant correlation with the latter(r=0.30, P<0.001). Postoperative scores and VA significantly improved compared with preoperative scores (tVA=13.44, tscores=16.75, P<0.001). The ES, SRM and CR were 1.71, 1.40 and 44.46%, respectively. The patients fell into three groups based onpreoperative VA and into two groups based on the presence of ocular comorbidity or whether surgery was performed on one or both eyes. Scores changed more in the absence of ocular comorbidity than in the presence of ocular comorbidity(t=2.90, P=0.004). Other analyses indicated that a change in scores showed no significant difference among subgroups. The distribution-based MCID was 1.80, 2.12 and 3.86 from 1 ES, 1 SEM and 1/2 SD, respectively. The score changes correlated with the GIC scale (r=-0.35, P<0.001). Linear regression yielded a beta coefficient of 3.74, which estimated the Catquest 9SF-CN MCID. Therefore, we propose an MCID of 2.88points. Conclusios: The Chinese 9-item Catquest short-form questionnaire is a valid patient-reported outcome measurement instrument for cataracts, and it is responsive to change in Chinese patients undergoing surgery. The MCID value of 2.88 points is established to provide reference for clinical application.