Abstract: The secondary consolidation coefficient has been considered constant in engineering. However, there are many research findings that the secondary consolidation coefficient is not a constant by means of laboratory test. The coefficient can change with the time. The secondary consolidation coefficient has nothing to do with the consolidation pressure. But many tests also show that the secondary consolidation coefficient has some correlations with the consolidation pressure, compression index, moisture content and plasticity index. This paper studies the secondary consolidation properties of soft cohesive soil in Beijing plain. It finds and analyses these relations. The results show that for the over-consolidated soil, the coefficient of secondary consolidation increases as the load increases. For the normal-consolidated soil, it decreases as the load increases. It also keeps a linear increase with moisture content and plasticity index. The ratio of Cα/Cc is a constant.