Objective A series of N-of-1 trials were conducted to evaluate the effect of traditional Chinese medicine (TCM) individualized syndrome differentiation on stable bronchiectasis, and to explore a clinical trial method that is consistent with the characteristics of TCM. Methods The original plan was for 3 cycles, with each cycle consisting of two observation periods: experimental and control. Take the medication for 3 weeks each period and then stop for 1 week. Because the results were not as expected, another cycle of trials was added (a total of 4 cycles). The trial period was treated with individualized syndrome differentiation prescription and the control period was treated with placebo. The outcome measures were Likert scale score of general symptoms (primary outcome), Likert scale score of respiratory symptoms, CAT score, 24h sputum volume and TCM symptom score. Data analysis (including residual effects and stage effects analysis) used group-designed independent sample t tests, paired t tests or non-parametric tests, mixed effects models, and Bayesian analysis. Results A total of 31 participants were formally enrolled, with 24 completing all four cycles. Independent sample t-tests and mixed-effects models showed no significant period or carryover effects. Bayesian analysis showed that there were residual effects on some outcome measures of some individuals. Six participants showed statistically significant differences in overall symptom Likert scale scores (P<0.05). Bayesian analysis found that TCM was more effective than placebo in more individuals. No significant differences were found between individualized TCM and placebo at the group level for all outcome measures. Conclusion This study method highly simulates the clinical practice of TCM, with good operability and patient compliance, and has no obvious residual effect of TCM on the whole, which can provide the best individualized evidence-based medicine evidence of short-term efficacy of TCM. Bayesian analysis can improve the sensitivity of individual statistics.