The resistive transition broadening of high Jc Ag-sheathed Bi(2223) tape has been systematically investigated in the field range of 0 to 1T. The experimental result shows that the resistive transition is of the thermally activated behavior. The relation between the flux pinning and the temperature has been studied. The temperature dependence of resistance is R(T) = R0exp [-μ0(1-T/Tc)n/kT] ,where n=4.5 for H//ab plane and n=3 for H⊥ab plane. When the magnetic field is parallel to ab plane, the dissipation is independent of the Lorentz force and only depends on the magnitude of the magnetic field parallel to ab plane. This behavior can be explained in terms of thermally activated pancakelike vortex-an-tivortex pair model. The mechanism of the flux pinning of the Bi-system material is discussed .