The neutral kaon meson mixing plays an important role in test of the Standard Model (SM) and new physics beyond it. Scale invariant unparticle physics induces a flavor changing neutral current (FCNC) transition of $K^0-bar K^0$ oscillation at the tree level. In this study, we investigate the scale invariant unparticle physics effects on the $K^0-bar K^0$ mixing. Based on the current experimental data, we give constraints of $K^0-bar K^0$ mixing on the unparticle parameters.