By according to a new type of pile-soil around coupling structure and starting from the soil arching effect, and analyzing the around the pile spacing of pile structure integrating the theory of M.M promojiyfakonov and flow around resistance within the adjacent, this paper concluded the calculation control type of the pile spacing, and provided a small soil arching between all around the piles were existing, and deduced the coupling calculation formula of structure for the diameter of piles and soil by coupling pile diameter and pile spacing, soil parameters, the change rule of the pile number. Research showed that there is more economic and reasonable in small and medium-sized slope engineering of clayey soil medium-based, using five or six hexagonal structure arrangement, the pile diameter of the pile spacing is 3-4 times, that it can achieve the best coupling effect, and lLay the foundation for the coupling structure of the engineering application.