In this paper, we study the deformed Hermitian-Yang-Mills equation on compact Kähler manifold with non-negative orthogonal bisectional curvature. We prove that the curvatures of deformed Hermitian-Yang-Mills metrics are parallel with respect to the background metric if there exists a positive constant C such that − 1 C ω < √ −1F < Cω. We also study the self-shrinker over C n to the corresponding parabolic flow. We prove that the self-shrinker over C n is a quadratic polynomial function. We also show the similar rigid theorem for the J-equations and the self-shrinkers over C n to J-flow.