Abstract: The effect of growth atmosphere and rate on the preparation of rutile single crystal in the flame fusion method was mainly studied in this paper. The annealed result in air was compared with it in oxygen. Swing curve and transmissivity of the sample were measured. It was made clear that crystal growth is influenced by chamber atmosphere, temperature at the liquid-solid interface and growth rate, and that the chamber atmosphere is an essential factor on whether crystal could be formed or not. To form a perfect crystal it's a necessary condition that the partial pressure of oxygen at the liquid-solid interface is higher than its decomposed pressure. The role of annealing is to relieve thermal stress formed in crystal growth. However, the more important role of annealing is the oxidization reaction to eliminate oxygen vacancies .The annealing time could be considerably shortened in oxygen. The crystal grown in the optimal experimental condition has good perfection and it's transmissivity is 70-72;, close to commercial crystal.