Abstract: The method of attitude determination with double satellites is discussed indetail in the paper, and the actual experiment of attitude determination with onlytwo GPS satellites is conducted. The long-short baseline method and sequenceoptindzation method are synthetically used to estimate carrier phase ambiguity.The experiment results indicate that the success rate of attitude deterndnationexceeds 90% and the mean square error of attitude can be less than 0.5°, whenbaseline length be 1 m around.