Abstract: The study of the tip-over stability of mobile manipulators in photovoltaic plants is crucial for ensuring their safe and efficient operation. This paper employs the gravity method to analyze the static stability of the mobile manipulator on both horizontal and inclined surfaces. Using the tip-over moment as a criterion, the stability of the coupled state between the mobile platform and the manipulator is assessed. Matlab and Adams simulations are utilized to verify the stability of the mobile manipulator. The results indicate that the mobile manipulator operates stably on horizontal surfaces. By analyzing the stability of the mobile manipulator on inclined surfaces, the maximum allowable slope angle for safe operation is determined.