Micro steel pipe pile is widely used in the reconstruction, reinforcement and rectifying of existing buildings considering that it is of high construction efficiency and environmentally friendly. The construction sequence would influence the effect of reinforcement or rectification and even the safety of the building. However, the research about influence of the construction sequence on displacement of the existing foundation reinforced by micro steel pipe piles is still relatively insufficient. Based on transparent soil material and particle image velocimetry (PIV) technology, this study performed the visual model test of reinforcing existing foundation via micro piles in different sinking orders (counterclockwise type, combined clockwise and counterclockwise type, Z type and symmetrical type), analyzed the displacement field of soil caused and the influence of different sinking orders on the cushion cap, pointed out the optimal strengthening scheme. The results indicate that under the test conditions, the pile under the cushion cap had a compacting effect on the surrounding soil. When the pile sanked around the cushion cap, the soil displacement around was less significant, and the soil disturbance zone was reduced by 42%, and the maximum displacement was reduced by 36% compared with the case of no cushion cap. The symmetrical reinforcement sequence was optimal, considering that the lifting displacement was only reduced by half.