Objective To explore developmental trajectory of tidal-breathing pulmonary function in preterm infants undergoing prone position combined with electric toothbrush-assisted vibration during non-invasive ventilation, analyze the characteristics of infants following the different trajectories, and identify the underlying influencing factors, so as to provide evidence for targeted clinical interventions. Methods From September 2023 to March 2025, 164 preterm infants diagnosed with respiratory distress syndrome were recruited by convenience sampling.All participants received a combined intervention of prone positioning plus electrictoothbrush vibration for sputum removal under non-invasive ventilation for 3-7 days.Tidal volume (VT) and minute ventilation (VE) were recorded before the intervention (T0) and on the third day (T1), the fifth day (T2) and the seventh day of the intervention.Latent growth mixture modeling was used to identify distinct developmental trajectories of VT and VE.Univariate analyses and logistic regression were further conducted to identify factors associated with different trajectory classes. Results A total of 164 premature infants were classified into three types of developmental trajectories according to their VT and MV, namely the significant improvement group (accounting for 53.66% and 57.93%, respectively), the slow improvement group (28.05% and 31.10%, respectively), and the risk fluctuation group (18.29% and 10.97%, respectively).Logistic regression analysis showed that gestational age, birth weight and serum albumin were influencing factors for the developmental trajectory of tidal-breathing pulmonary function in preterm infants (all P＜0.05). Conclusion The developmental trajectories of tidal volume and pulmonary function in preterm infants receiving prone positioning under non-invasive ventilation combined with electric toothbrush-assisted vibration generally showed an improving trend, yet significant heterogeneity existed among subgroups.Clinical healthcare providers should pay particular attention to preterm infants with lower gestational age, lower birth weight, and lower serum albumin levels, closely monitor their dynamic changes in tidal-breathing pulmonary function, and develop targeted intervention strategies to enhance the pulmonary function and promote recovery.