Abstract: The thermodynamic properties of the two-sublattice Ising metamagnet under the action of both transverse field Ω and the longitudinal field h are studied with the mean-field theory. When the parameter α, i.e., the intensity ratio of interlayer spin coupling to intralayer one, is equal to zero, the internal energy, heat capacity, longitudinal staggered magnetization, longitudinal total magnetization and transverse total magnetization are all calculated to reveal how the internal energy and heat capacity change with temperature. The transverse field Ω enables the internal energy and heat capacity in the system to decrease, thus affecting the thermodynamic properties of Ising metamagnet greatly.