An exhaust manifold heat dissipation cover coupling device for thermal stress and vibration deflection is proposed. The device has a function of preventing wear of a heat dissipation cover to couple an exhaust manifold heat dissipation cover, the device being able to improve the durability of various parts including a heat dissipation cover by attenuating multi-directional vibration that is transmitted from an exhaust manifold when the heat dissipation cover is installed outside the exhaust manifold, being able to prevent damage to parts due to thermal stress by flexibly coping with thermal deformation such as thermal contraction or thermal expansion even if the thermal deformation is generated by high-temperature heat transmitted from the exhaust manifold, and being able to prevent frictional damage of the heat dissipation cover due to friction by a component that slides to attenuate vibration.