Abstract: Physical model test of landslide body containing gravel and soil reinforced by the micro-pile composite structure was carried out under two ratios of spacing to diameter. Deformation of the structure was analyzed for acquiring the influence of ratio of spacing to diameter on the anti-slide performance. The test results show that deformation of the structure can be divided into three stages no deformation stage , elastic anti-slide stage, and the elastic-plastic failure stage; then, when displacement at top of the pile exceeds 3.6% of the length of the pile, the structure enters the phase of plastic failure; subsequently, beams at the top of the pile effectively constrain displacement of the pile, so that inflection point occurred at the height of l₂/8 measured upward from slip surface, where l₂ is the freedom length of the pile; moreover, the bending moment of pile was larger when the location is at the height of l₂/5 above slip surface and l₁/10 below the slip surface, where l₁ is the embedded length of the pile, and the maximum bending moment is located at the height of l₂/20 above slip surface; finally, as ratio of spacing to diameter is less than 7.5, wedging effect of soil on micro-pile composite structure is stronger and the pile can withstand greater landslide thrust.