The existence of dark energy is one of the most significant cosmological discoveries over the last century. Various models of dark energy have been proposed, such as Holographic Dark Energy. In this model of dark energy, cosmologists try to estimate the entropy of whole world based on the area of the universe. But w hat is the surface of the universe? In the context of black hole physics, we believe that the event horizon of a black hole is the proper surface since every physical quantity of the black hole, especially the entropy, shows itself properly on that surface. And they strictly obey the first law of the thermodynamics. But in the general solution for holographic dark energy, there are several evidences that show the apparent horizon should be a causal horizon and is associated with the gravitational entropy and Hawking temperature. Hence it seems that the apparent horizon is the right holography of the universe. There are decisive evidences that our observable universe evolves adiabatically after inflation in a comoving volume, that is, there is no energy-momentum flow between different patches of the observable universe, so that the universe keeps homogeneous and isotropic after inflation. That is the reason why we can use an FRW geometry to describe the evolution of the universe. Based on these postulates, cosmologists proposed a model, evaluating cosmological components such as deceleration parameter, effective pressure of dark energy and dark matter and equation of state of these dark components in the holographic dark energy model in the flat space time. In this proposal, we try to generalize that model and calculate the quantities of the holographic dark energy model in the curved space time. In our results it is obvious that the evolution of the model in the open space time is the same as the flat space time. But in closed space time, results are different. Consequently, we can conclude that our universe can be flat (or open) in the holographic dark energy model. We find that under this condition the dark energy must evolve non-adiabatically. But the total matter in a comoving volume should evolve adiabatically. Hence a compensating component should exist, which we called dark matter. The final ratio of dark matter to dark energy only depends to $ omega _{ de e} $ and $ omega _{ dm e} $ , which is independent on the initial values of the densities of dark matter and dark energy. This result is helpful to solve the coincidence problem. In a numerical example, we find that the deceleration parameter can be well consistent with observations. All of all, By assuming that dark energy in the universe obeys the holographic principle, based on the first low of thermodynamic and by using the methods of dynamical system analysis, we find that there exists a stable dark energy-dark matter solution at late time in the curved space time, which is helpful to solve coincidence problem. For reasonable parameters, the deceleration parameter is well consistent with current observations. Keywords: Holographic dark energy, Dark matter, Cosmology