A plume impingement analysis on the thruster deck and the membrane of IKAROS was performed based on available flight data. IKAROS employs gas-liquid thruster system as RCS for spin-rate adjustment and attitude control. Gas jet plume from the thruster nozzles leads to considerable undesired disturbance force on the spacecraft, because IKAROS has a large size of flexible membrane whose diagonal distance is 20m. To minimize thrust loss by means of improvement in maneuver planning and to obtain the local distribution of the momentum flux on the membrane for future solar sail missions design, it is important to evaluate the plume impingement on the solar and propose a plume distribution model. Therefore this paper presents actual values of mechanical load on IKAROS and provides a distribution of plume force on the surface. In proposal of a plume model, the conventional plume density distribution model  and plume impingement model  were used. And parameters in these models that describe the physical interaction between plume flow and the surface of membrane were identified based on fight data.