Objective: This study aimed to investigate the impact of obesity on left ventricular mechanical contraction synchrony parameters in patients with normal myocardial perfusion imaging. Methods: A retrospective analysis was conducted on patients who underwent CZT SPECT myocardial perfusion imaging at the First Affiliated Hospital of Nanjing Medical University from January 2023 to August 2024. 133 patients with normal MPI results and left ventricular ejection fraction were included. They were divided into three groups according to body mass index (BMI): 40 cases in the normal group (BMI≤23.9), 45 cases in the overweight group(24≤BMI≤27.9), and 48 cases in the obesity group (BMI≥28). The differences in left ventricular function parameters such as PBW, PSD, EDV, ESV, and LVEF among the three groups were analyzed, and the influence of BMI on these parameters was explored. Results: The PBW (22.00±4.24 vs 17.10±3.20, p<0.001; 26.13±5.74 vs 17.10±3.20, p<0.001) and PSD values (5.04±1.05vs3.74±0.68, p<0.001; 6.34±1.43vs3.74±0.68, p<0.001) in the overweight and obesity group were significantly higher than those in the normal group. The PBW (26.13± 5.74 vs 22.00±4.24, p<0.001) and PSD values (6.34±1.43 vs 5.04±1.05, p<0.001) in the obesity group were significantly higher than those of overweight, and the difference was statistically significant. Body mass index (BMI) was significantly positively correlated with PBW (r=0.446, p<0.001) and PSD (r=0.477, p<0.001) in overweight and obesity patients. Conclusion: Obese patients are more likely to develop LVMD, and the novel cadmium-zinc-telluride SPECT phase analysis can effectively evaluate LVMD in obese patients at an early stage. This has significant clinical guiding significance for the early detection of LVMD in obese patients and the implementation of intervention to reduce cardiovascular events.