Objective. To explore the effects of improved oral care on the number of oropharyngeal bacteria and the incidence of ventilatorassociated pneumonia in patients undergoing mechanical ventilation through oral endotracheal intubation by improving conventional oral care methods and operating procedures and to evaluate the quality of improved oral care and effect. Methods. A total of 100 cases of mechanically ventilated patients with oral endotracheal intubation who met the inclusion criteria were randomly divided into the observation group and control group with 50 cases each. The control group took routine oral care, that is, scrubbing 3 times per day, and the oral care solution was selected as physiological brine. The observation group improved the conventional oral care method, namely, oral scrubbing before intubation, brushing and washing after intubation, 3 times per day, and 0.1% povidone-iodine in oral care solution. Analysis and comparison of the oral bacterial flora, oral cleanliness, and incidence of ventilator-associated pneumonia, mechanical ventilation time, ICU hospitalization time, and mortality rate of the two groups of patients were analyzed and compared. The relevant data were collected and processed for statistical processing. Results. The oral bacterial flora of the two groups of patients before oral care after mechanical ventilation after oral tracheal intubation was compared, and there was no significant statistical difference (P > 0:05). After nursing, the oral bacterial flora of the observation group at 8 h, 16 h, and 24 h after intubation was significantly lower than that of the control group. Statistics showed that the difference was statistically significant (P < 0:05). After nursing, the number of patients with oral cleanliness in the observation group was significantly higher than that of the control group, while the incidence of ventilator-associated pneumonia in the observation group was 8% significantly lower than that of the control group 14%. Statistics show that this difference is statistically significant (P < 0:05). After nursing, the observation group's oral cleanliness score, mechanical ventilation time, ICU hospitalization time, and GCS score were better than those of the control group. Statistics showed that the difference was statistically significant (P < 0:05). The mortality of the observation group was significantly lower than that of the control group, which was not statistically significant (P > 0:05). Conclusion. Oral care can effectively reduce the number of oropharyngeal bacteria in patients who are mechanically ventilated through orotracheal intubation and significantly reduce the incidence of ventilator-associated pneumonia.