  The general reflection and refraction laws at the metasurface with the abrupt
phase shift were derived by two different methods of Fermat's principle and the
boundary conditions respectively. It is found that one or two critical angles
for total internal reflection exist when a light hits on the optical sparse
material from the optical denser material, and one such a critical angle exists
when light spreads from the optical sparse material to the optical denser
material. Anomalous reflection and refraction, such as, negative reflection and
negative refraction may occur when a light passes through the metasurface, and
the conditions of their occurrence were given. Finally, a kind of metasurface
based on one-dimensional phase mask was designed to control the light
propagation.
