The invention provides an A-phase vanadium dioxide nanowire preparation method. The A-phase vanadium dioxide nanowire preparation method is characterized in that due to the addition of a surface active agent, an intermediate phase B can be rapidly converted into A-phase vanadium dioxide, and an A-phase vanadium dioxide nanowire with excellent morphology and draw ratio is formed; the prepared A-phase vanadium dioxide nanowire is very pure and stable. The preparation method is simple in raw materials, convenient to operate and easy to control; the crystallinity of the product is good; the nanowire can be widely applied to the fields such as batteries, hydrogen storage, photoelectric switches and the like.