Abstract: Following its first successful development of the HFW submarine linepipe in 2006, CNOOC Kingland Pipeline Co., Ltd.in 2009, succeeded in developing the X70 HFW steel pipe.Described in the paper are the R&D of the X70 HFW submarine linepipe by the company.The R&D result shows that the said X70 linepipe has been in compliance with relevant requirements as specified in Specifications DNV-OS-F101-2007 and GB/T9711.3-1999 (Grand C Steel Tube), having met the targets of the R&D project.