The preparing method of (BiPb)-Sr-Ca-Cu-O 2223 phase high-Tc superconductor is introduced. The magnetic relaxation rate dependence on applied magnetic field was measured by using a vibrating sample magnetometer. From the above results, the relationship of activation energy U0 vs. applied magnetic fuild B is discussed. We found that the functional form is U0-B-a in the magnetic field range of 0-0.23 T. The results is similar with that of Pa-lstra based on resistance broadening experiment for single crystals.