The structural calculation of high pile wharf could starts with the upper structure calculation by fixing the pile at a certain depth, and is followed by the analysis of pile-soil interaction by applying the calculation of internal force as a load to the pile. In theory, the most reasonable location for the embedded point can be identified under the condition that the horizontal displacement of pile top equals before and after simplification, but in practice it is difficult to achieve. Combining with the data of the field loading test, this paper conducts an extended analysis of the embedding characteristics of the super-long piles under the horizontal load and puts forward the experience formula of the embedded depth which changes with load. Calculation results show that the effect is satisfactory.