In order to simulate the adaptability and the fluctuation resistance ability of simulation inspection device and hanging ladder on ground, simulation inspection device and multi-grade centroid adjusting mechanism are designed in this paper. In the process of centroid adjusting, modification of the centroid position is transformed by means of mathematical model into a certain centroid adjusting mechanism, which is relative to displacement of Y Axis in calculating coordinate system and angle alternation between the adjustable centroid lever and the main rocker. The results show that the calculation is in good agreement with the analysis.