We first recall some techniques of scalar curvature flow on Sn developed in my previous paper joint with Professor Xingwang Xu (Invent. Math. 2012). Next, we extend such a flow approach to prove a perturbation result of the fractional Nirenberg problem, i.e. prescribing fractional Q-curvature problem on Sn for n >= 3 and the fractional exponent ½ < σ < 1. This is joint with Pak Tung Ho and Jingang Xiong.