Abstract: This paper puts emphasis on the problem of the developing flows in the circular tube under oscillatory conditions.According to the Navier-Stokes' equation and using the method of Bessel function of imaginary argument, a system of formulas is obtained.Comparing the formulas obtained in this paper with A tabek's formulas, it may be seen that the former is simpler and more convenient.When both the formulas obtained in this paper and A tabek's formulas are reduced to the representation of developed flows, both of them are consistent.Numerical calculation results show that the computed results obtained in this paper are rather consistent with both A tabek's computed results and the experimental results.