The coefficient of consolidation is one of most important parameters for reinforcement of soft ground with drainage method.The parameter obtained from back analysis with in situ data would be more consistent with the actual situation,because the test conditions of the laboratory and field are quite different.Based on the in situ settlement data of some soft ground treatment projects,this paper analyzes various kinds of effects on consolidation parameters from the aspect of total load,load ratio before and after full load,pre load time ratio and changes in boundary conditions beside the in situ points,and fits relationship formula according to changes with the parameter.Furthermore,it proposes a simple algorithm with the immediate settlement,and calculates the primary consolidation zero point of time,which is compared with the revised zero point obtained from Zeng Guo xi method.The results may serve as reference for the engineering and research concerning soft ground treatment project.