Large segment sand control is adopted in Bohai Oilfield,and there are still have small layers in the large segment.As the nonhomogeneity of the resevior is severe,the interference between the layers is sever,the effect is hard to improve.Beside the packer set outside the sand control string between the layers,the packer inside the sand control string is also needed.For different layered injection or production styles,crossing expandable packer was developed.The application environment,structure and principle of the packer were introduced.From the lab test and the field test,it can be seen that the pipe that external diameter is 6.35 mm can cross the packer smoothly without any resistance;the protection function of the packer can protect the pipe effectively;the packer can seating or release smoothly,while the pressure is added at 16 MPa; the upper or under annular space can resist pressure at 15 MPa,also the packer can seal the space while the inner diameter is 157.1 mm.So the packer satisfies different application conditions.