  For Anti-de Sitte (AdS) black holes, the isochoric heat capacity of system is
vanished, while the isobaric heat capacity is not. However, this situation does
not hold on for de Sitter (dS) black holes. In this work, by introducing the
interaction between the black hole horizon and the cosmological horizon of the
Reissner-Nordstr\"om-de Sitter (RNdS) spacetime with quintessence, we discuss
the phase transition of this system. The results show that the spacetime not
only has the similar phase transition behavior to that of Van der Waals (VdW)
system, and the non-vanishing isochoric heat capacity fulfills the whole
thermodynamics system. Through the discussion of the entropic force between two
horizons, we find out the role of entropic force in the evolution of spacetime.
In addition, we also study the influence of various parameters on the phase
transition and entropic force, which will provide a new method for exploring
the interaction among black hole molecules from a micro perspective.
