Abstract: As a new kind of in-situ test technique originated in 1980s, the piezocone penetration test (CPTU) has especially been fit for engineering investigation of soft clay and commonly used in the western developed countries because of its advantages. In the first place, the paper introduces the development of CPTU in brief, expounding the equipment and operation procedures. With summarizing literature works, the engineering properties of soft clay are evaluated from CPTU data, particularly in the evaluation of stress history, strength, deformation, consolidation and permeability characteristics. Finally, some conclusions on the CPTU are finally presented.