Objective: To evaluate VAP prevention behavioral characteristics and barriers among ICU physicians, nurses, and cleaners based on the Transtheoretical Model (TTM), and to verify the application effects of a stratified intervention model. Methods: A quasi-experimental study was conducted. In June 2025, a convenience sample of 205 ICU staff from 7 ICUs of a tertiary hospital was recruited. A self-designed questionnaire was used to construct the model, which was implemented for 6 months to compare behavioral stages and VAP incidence. Results: Before the intervention, significant differences were observed in behavioral stages among the groups (p < 0.05). The maintenance stage proportions for physicians, nurses, and cleaners were 71.87%, 41.14%, and 13.33%. After intervention, they increased to 84.38%, 58.23%, and 33.33%, respectively (p < 0.05). Subglottic secretion drainage compliance among nurses increased from 41.77% to 89.24%, and environmental cleaning compliance among cleaners increased from 26.67% to 86.67% (p < 0.05). VAP incidence decreased from 3.14 to 1.21 per 1,000 ventilator-days (p < 0.05). Conclusions: The model precisely matches occupational needs, promotes positive behavioral shifts, improves compliance, and significantly reduces VAP incidence.