Abstract: In this paper，the formula of aberration is direct derived by the principle of constancy

of light veloci- ty without the Lorentz transformation. This method has much in common with the

methods of deriving the time dila- tion effect and the length contraction effect. It can be used

as the extended discussion or the practice after class in the lesson of the principle of constancy

of light velocity.

Key words: the principle of constancy of light velocity, aberration, special relativity