Micro steel pipe pile is widely used in the reconstruction, reinforcement and rectifying of existing buildings due to its high construction efficiency and environmentally friendly technology. The construction sequence would influence the effect of reinforcement or rectification and even the safety of the building. However, the research on the influence of the construction sequence on the displacement of the existing foundation reinforced by micro steel pipe piles is still relatively insufficient. Based on transparent soil material and digital image processing technology, the visual model test of reinforcing existing foundation via micro piles in different sinking order (counterclockwise type, combined clockwise and counterclockwise type, Z type and symmetrical type) was carried out, analysised the displacement field of soil caused by the reinforcement and the influence of different sinking order on the cushion cap, and pointed out the optimal strengthening scheme. The results indicate that under the test conditions in this paper, the pile under the cushion cap had a compacting effect on the surrounding soil. When the pile was sanked around the cushion cap, the soil displacement around the pile under the cushion cap was small, and the soil disturbance range was reduced by 42%, the maximum displacement was reduced by 36% compared with the case of no cushion cap. Under the test conditions in this paper, the symmetrical reinforcement sequence was relatively optimal, and the lifting displacement of the existing foundation in the construction process was only 56% of that of the most unfavorable reinforcement sequence.