A method of calculating elastic curve for semiflexible plate wind tunnel nozzle has been presented，based on the linear theory of small deflection of beam deformation，in this paper. In light of the match results of curvature between flexible plate calculated and aerodynamic contour，the reasonable arrangment of jacks on the plate，which has an obvious effect on the curvature match，is of vital importance. So the structure designer of flexible nozzle should be cautious of it.