A procedure for determining the lift and pitching moment derivatives of not so slender wing-body combination in supersonic flow is presented. It is based on an introduced extension of the approximate slender body theory by retaining additional terms that have been neglected by virtue of body slenderness.The extension included the dependence of the solution on body geometry and flow Mach number. An application is given for the case of thin flat triangular wing mounted on conical pointed body. Computed results are compared with the original theory and other publish-ed theoritical and experimental data where good agreement is obtained.