Abstract: Described in the paper is the effect by the dimension accuracy on fatigue-resistance of the seamless steel pipe used as the deep-water steel catenary riser.The key factors affecting the rolling dimension accuracy of the seamless steel pipe are analyzed.As a result,the small-lot trial production of the riser-purposed seamless steel pipe is successfully carried out by means of such actions as properly controlling the homogeneities of both the chemical composition and heating of the billet,controlling the total rolling number and the assembly accuracy of the pipe-rolling tools and dies,and ensuring the central line accuracies of the facilities on the rolling line as well as the boring accuracy of the pipe end.The pipe end wall thickness accuracy and pipe end ID accuracy of the sample pipe as processed are separately ±1.0 mm and ±0.25 mm,which has met applicable technical requirements.