Abstract: The II-type and O-type expansion loops are the common compensators used in compensating the thermal deformation of steam injection pipeline of heavy oil recovery in oilfield. However, the defects exist in the structures' design of the two compensators. For the former, more supports will be needed, and more heat will lose; while the later, the rupture and leakage are easier to occur. The natural compensating method (the new compensating method)which, by adopting overlong pipe in longitudinal piping section, uses the L-type and Z-type expansion loops formed at angle pipe and barrier, is introduced. It can compensate the thermal deformation of pipe with the unsteady deformation of unsteady condition of the pipe when the pipe is forced. The calculation for the longitudinal piping section has been made, the conclusion is that the strength of pipe is enough to compensate the deformation. Meanwhile, the economic evaluation of capital investment and energy saving have been made for the three expansion loops of steam injection pipeline.