Abstract: In this paper, we have investigated the ground states of a few-layered fcc thin film of binary alloy with two surfaces in the (001) direction under symmetric surface confinement. The phase diagram of the ground states is given according to the energy analysis of binary alloy thin film composed of six atomic layers in the (001) direction. Surface confinement field (SC field) is introduced as a term to describe the confinement on the two surfaces in the (001) direction. Using Monte Carlo simulation, we have found that there are 17 different ground states occurring when both SC field and chemical potential vary from - to + . Antiphase boundary(APB) was found in 12 of the 17 ground states, and only nine configurations with different symmetry were found among the 17 ground states.