  A semi-classical reasoning leads to the non-commutativity of space and time
coordinates near the horizon of static non-extreme black hole, and renders the
classical horizon spreading to {\it Quantum Horizon} . In terms of the
background metric of the black hole with the {\it Quantum Horizon}, a quantum
field theory in curved space without ultraviolet divergency near the horizon is
formulated. In this formulism, the black hole thermodynamics is reproduced
correctly without both ambiguity and additional hypothesis in the deriving the
hole's Hawking radiations and entropies, and a new interesting prediction on
the number of radiative field modes $N$ is provided. Specifically, the main
results are follows: 1, Hawking radiations rightly emerge as an effect of
quantum tunneling through the quantum horizon, and hence the ambiguities due to
going across the singularity on the classical horizon were got rid of; 2, 't
Hooft's brick wall thickness hypothesis and the boundary condition imposed for
the field considered in his brick wall model were got rid of also, and related
physics has been interpreted; 3, The present theory is parameter free. So, the
theory has power to predict the multiplicity $N$ of radiative field modes
according to the requirement of normalization of Hawking-Bekenstein entropy. It
has been found that $N\simeq 162$, which is just in good agreement with one in
the Minimal Super-symmetric Standard Model. The studies in this paper represent
an attempt to reveal some physics near the horizon at Planck scale. This paper
serves a brief review on the author's works on this subject.
