Objective To evaluate the changes of right ventricular function in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) before and after continuous positive airway pressure (CPAP) treatment by two-dimensional speckle tracking imaging (2D-STI). Methods Fifty patients with moderate and severe OSAHS were selected for CPAP treatment, and another 40 healthy volunteers were selected as a control group. 2D-STI and traditional echocardiography were conducted in the study group before treatment, after 3 months of continuous treatment and after 6 months of continuous treatment and in the control group. Results The differences between the control subjects and the OSAHS patients were statistically significant in right ventricular global longitudinal strain (RVGLS), right ventricular free lateral wall longitudinal strain (RVLLS), apical segment of the right ventricular free wall longitudinal strain (Apical RV-SL), basal segment of the right ventricular free wall longitudinal strain (Basal RV-SL), and media segment of the right ventricular free wall longitudinal strain (Media RV-SL) (all P<0.05). RVGLS, RVLLS and Apical RV-SL were significantly improved after 3 months of CPAP treatment (all P<0.05). Basal RV-SL was significantly improved after 6 months of CPAP treatment (P<0.05). Conclusions The right ventricular function of patients with OSAHS is abnormal. CPAP treatment can improve the right ventricular function of OSAHS patients. 2D-STI can accurately assess the changes of right ventricular function.