Several one-dimensional nanomaterials(wires and rods) of BaCO3, were synthesized in the presence of the nonionic w/o micro-emulsions of Tween-80, Triton X-100 and C12E9. The intermediate and middle course of BaCO3 nanowires formation were captured, and the formation mechanism of the one-dimensional nanomaterials was conjectured as directional aggregation of BaCO3 colloid particles controlled by soft microemulsion template.