In order to discuss the mechanical and deformation behavior of piles in coastal soft soil areas under horizontal load，the corresponding simplified mechanical model was established according to the loading characteristics of piles in coastal soft soil areas.Secondly，the softening effect of coastal soft soil was considered to modify the existing p-y curve model.On this basis，the differential equation of pile deflection in coastal soft soil areas was derived，and its internal force and displacement were solved by the transfer matrix method.A nonlinear calculation method of piles in coastal soft soil areas considering the softening effect was obtained.Finally，the influence of softening parameters，pile diameter，and elastic modulus of pile on the horizontal bearing capacity of piles was analyzed with relevant engineering cases.The results show that the transfer matrix method has high precision and calculation efficiency in the analysis of piles in soft soil areas under horizontal load，which can provide a reference for related projects.When the softening parameter increases by 0.3，the horizontal displacement of the pile at the ground decreases by 24.12% and 43.04%，respectively.When the pile diameter increases by 0.7 m，the horizontal displacement of the pile at the ground decreases by 62.63% and 79.65%，respectively.The influence depth of the pile displacement and internal force increases with the increase in the pile diameter.When the elastic modulus of the pile increases from 25.5 GPa to 36.0 GPa，the deformation of the pile decreases by 6.25% and 23.06%，respectively.