In soft soil improvement projects, analysis of measured settlement data is often limited to predication of ultimate settlement and consolidation degree.Based on the Asaoka method, complete procedures for dynamic design of soft soil improvement can be established by using the measured settlement data.This paper summarizes the method of calculating the ultimate settlement and consolidation degree under preloading by Asaoka method, and puts forward a practical method for back analysis of soil parameters such as horizontal consolidation coefficient and compression index，and prediction of preloading period.Its application is introduced through an engineering example.The procedures can make full use of the measured data, and dynamic design for soft soil improvement is realized, which are beneficial for design and construction.