Objective To explore the effects of active cycle of breathing techniques combined with pulmonary rehabilitation exercise training on heart rate variability (HRV) and pulmonary function in patients with chronic obstructive pulmonary disease (COPD) during convalescence. Methods The clinical data of patients with COPD during convalescence who were treated in the hospital between August 2017 and August 2019 were analyzed.36 cases randomly selected from patient with routine pulmonary rehabilitation training were included in routine training group, and 36 cases from patients with active cycle of breathing techniques (ACBT) intervention were randomly selected as ACBT group, and 36 cases who were randomly selected from patients receiving routine pulmonary rehabilitation training combined with ACBT were set as routine training+ACBT group. The HRV indicators［standard deviation of NN intervals (SDNN), root mean square values of the standard deviation between adjacent normal number of intervals (rMSSD), percentage between RR and the period＞50ms (PNN50), low frequency (LF), high frequency (HF)］, pulmonary function indicators ［forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF)］, rehabilitation status［6min walking distance (6MWD), Borg dyspnea score (BS)］and quality of life (CRQ score) were compared among the three groups before intervention and after 12 weeks of intervention. Results After 12 weeks of intervention, the HRV indicators, pulmonary function indicators and CRQ score in the three groups were obviously higher than those before intervention, and the above indicators of routine training+ACBT group were significantly higher than those of ACBT group and routine training group (all P＜0.05). The 6MWD scores of the three groups of patients after 12 weeks of intervention were significantly improved compared with those before intervention (all P＜0.05) while the BS scores were obviously reduced compared to before intervention (all P＜0.05), and the 6MWD score of routine training+ACBT group was significantly higher than that of ACBT group and routine training group while the BS score was significantly lower than that of ACBT group and routine training group (all P＜0.05). Conclusion Active cycle of breathing techniques combined with pulmonary rehabilitation exercise training for patients with COPD during convalescence can effectively improve the heart rate variability, enhance the pulmonary function, promote the rehabilitation and improve the quality of life, with good application value.