Abstract: By calculating the Bohr-radius of hydrogen atom with the assumption of Bohr theory,uncertain relation,Schrdinger＇s equation and wave function,the semi-classic and the semi-quantum in the assumption of Bohr theory can be comprehended deeply.The uncertain relation is proved as the result of the undulatory theory for micro-particles.The electron in hydrogen atom obeys the Schrodinger＇s equation.The solution of the equation is a wave function,namely a probability wave.

Key words: basic assumption of Bohr theory, uncertain relation, Schrdinger＇s equation, wave function