In this talk, we discuss the homogenization of a highly oscillating obstacle problem using the viscosity method. The equation we deal with is a non-divergence type equation with oscillating coefficients. To analyze the behavior of solutions in the obstacle problem, we construct a corrector function, periodic function when the obstacle is given as 1. By utilizing this corrector, we identify the so-called strange term behavior when the size of the domain where the obstacle is defined reaches a critical value. We then modify the corrector for critical size and analyze the solution`s behavior when the size of the obstacle is either larger or smaller than the critical value.