We study the intrinsic optical bistability（OB） of nondilute suspensions of coated spherical particles with a metallic core and a nonlinear dielectric shell. In this kind of system， as the spatial local field is not uniform, it cannot be obtained exactly. In this connection，we establish the self-consistent mean field approximation， and obtain the spatial average of the local field squared in the core as a function of the external applied field. Numerical results show that the optical bistability（OB） is dependent on the temperature T， the structural parameter k， and the volume fraction f. For given k and f， the width of optical bistability decreases with increasing temperature. At further increasing of T， OB is found to vanish. On the other hand， for given T and f， the bistable region gradually increases as the structural parameter k increases， accompanied with the increase in both the upper and lower threshold fields. More exactly， the increase of the bistable region mainly results from the rapid increase in the upper threshold field.