  We study the thermodynamics and the different thermodynamic geometric methods
of Reissener-Nordstr\"{o}m-de Sitter black hole and its extremal case, which is
similar to the de Sitter black hole coupled to a scalar field, rather called an
MTZ black hole. While studying the thermodynamics of the systems, we could find
some abnormalities. In both cases, the thermodynamic geometric methods could
give the correct explanation for the all abnormal thermodynamic behaviors in
the system.
