A transonic unsteady aerodynamic code called MM has been developed for the analysis of aircraft wing with pylon and external store. The MM code uses a time-accurate approximate factorization (AF) algorithm for the solution of the unsteady transonic small-disturbance equation. A finite-difference method is used in the space and also Engquist-Osher difference method is applied to achieve the numerical stability in the strong shock wave region. In this study, the results of analysis and comparison are presented for the F-5 fighter wing with tip missile and under sore missile to demonstrate the pylon/store aerodynamic capability of present TSD3KR code. These results are in a good agreement with NAL experimental steady and unsteady pressure data. But, it is shown that there are some differences in the region expected strong shock interaction between wing and pylon / store.