Vietnam traditional clothing is Ao dai. Ao dai is one of Vietnamese culture, the symbol of Vietnamese women. In high school white Ao dai has become girls uniform. Although high school girls was fond of Ao dai, it was difficult for movement, especially for every day wear. Through investigation into schoolgirls about Ao dai. In this paper, we proposed to combine analysis data with traditional Ao dai design to research and reform Ao dai in such a way that it made schoolgirls wear to feel more comfortable. The samples which was made according to patterns data, one again was evaluated on fitting, appearance and comfort.