The obstruction class $m_0$ in Lagrangian Floer theory is defined by counting holomorphic disks bounded by a Lagrangian submanifold. We generalize the notion of obstruction to our de Rham version of Fukaya category. We also prove that every flat vector bundle is isomorphic to a twisted complex of flat line bundles in Fukaya category under certain conditions. We also compare the obstruction of a flat vector bundle and the Maurer-Cartan equation of the corresponding twisted complex.