The invention provides a positioning method in a software defined wireless sensor network. The method comprises the steps of setting a contribution matrix for nodes in a network, wherein a certain element in the matrix is the contribution value of an anchor node in the row which corresponds with the element to a blind node positioning result in the line that corresponds with the element; according to the set matrix, constructing an optimization problem by means of knowability of a controller in the software defined network to global network information, selecting a positioning node from all anchor nodes for the blind node through a 0-1 programming method, wherein a requirement that the sum of powers of selected links is not larger than the total power of the wireless sensor network is satisfied, and maximizing the contribution value of the selected links in the network on condition that the requirement is satisfied; and calculating the position of the blind node by means of a linear least square algorithm by means of the known position information of the selected positioning node. The positioning method can be used for selecting a node which most facilitates positioning on condition that the power of the wireless sensor network is limited and furthermore improves positioning precision.