Abstract: Based on the formation principle and process of the yarn in air jet vortex spinning(i.e.Murata vortex spinning or MVS),this paper discusses the spatial track of the fiber in air jet vortex spun yarn.The results show that the spatial configuration of the fiber is affected by parameters,such as delivery speed V_y,the distance L from the nip of front roller to the inlet of the hollow spindle,the mean angular velocity for a rotating fiber ω_f,fiber length l,and yarn diameter d_y and so on.When the V_y value and the L value are held fixed,the l value is bigger,and the core fiber length l_c is longer.When the V_y value and the l value are held fixed,the smaller L value will result in the bigger l_c value.For given the ω_f value and the V_y value,the wrapper width with increasing wrapper radius,l_(mw),increases along with increasing the d_y value.For given the d_y value and the V_y value,the l_(mw) value decreases along with increasing the ω_f value.For given the d_y value and the ω_f value,the l_(mw) value increases along with increasing the V_y value.For given the V_y value and the ω_f value,the wrapper number and width l_(rw) for the regular wrapper decreases along with increasing the d_y value.For given the V_y value and the d_y value,the wrapper number for the regular wrapper increases along with increasing the ω_f value,however,the l_(rw) value decreases along with increasing the ω_f value.For given the d_y value and the ω_f value,the wrapper number for the regular wrapper decreases along with increasing the V_y value,however,the l_(rw) value increases along with the V_y value.