  This article puts forward a hypothesis.In this article, the derivative of the
cosmological constant is positive, and there is a possibility that the constant
evolves from negative in the early universe to positive in the later period. We
see that when the black hole is an extreme black hole $r_{+}=r_{-}$, the
curvature scalar vanishes to zero. In general, the curvature scalar is not
equal to zero. When $r_{+}=3 r_{-}$, the curvature scalar is equal to negative
infinity. According to Ruppeiner's theory, this time represents the phase
transition of the system. It is very interesting that the divergence point of
the curvature scalar happens to be the Davis transition point. We have found
the phase transition point of the new Schwarzschild black hole.
