Composite column of PBS method consists of precast concrete blocks and filled-in concrete and steel pipe pile. The authors conducted the serial tests in order to clarify the stress changes of introduced prestress due to the drying shrinkage and creep by means of monitoring strains and carried out the mechanical tests for comparing the theoretical values. The results of this study show that the stress losses due to the drying shrinkage and creep could be taken by a few theoretical formulas and that the stress state in this composite structure could be obtained by creep factor and strain of drying shrinkage stated in the Standard Specification for Design and Construction of Concrete Structures by JSCE.