Abstract: In 1905, Einstein submitted three important papers to ＂Annalen der physik＂ of Germany. Soon two of the papers were evaluated by the German physics community with Plank as the leader; in 1909 Einstein was invited to attend Salzburg conferences for the first time, In the report ＂On the Development of Our Views Concerning the Nature and Composition of Radiation＂ Einstein further expounded the two hot issues on the principle of relativity and optical quantum hypothesis. This speak caused a great stir, and enabled him to enter world-class physicists core layer once and for all.

Key words: Einstein, optical quantum hypothesis, Salzburg conferences