Abstract: The importance of straightness for ensuring quality of the HFW steel pipe is explained,and the common causes as responsible for the pipe’s straightness are analyzed, including improper setting of the straightener stand,inhomogeneous strength distribution of the coil,uneven temperatures on top and bottom surfaces of the pipe, and insufficient sizing amount,etc. And how such factors lead to bending of the pipe is revealed. Accordingly,preventative actions are put forward. Finally,it is concluded that the said influencing factors could be thoroughly eliminated, and desired straightness of the HFW steel pipe ensured by means of improving the cooling system,adding requirement for strength homogeniety of the coil,and assurance of sufficient sizing amount of the sizing mill,etc.