Harp shaped cable-stayed bridges without backstays are popular due to their beautiful and unique styles; they employ leaning tower columns to balance the constant and movable loads on the decks and are not provided with backstays, so they are beyond the traditional bridge design philosophy. In this paper, we discussed the reasonable structure of the main girder of Changsha Hongshan Bridge – a harp shaped cable-stayed bridge without backstays through changing the design parameters of the main girder in respect of design so as to provide important reference for design of this kind of bridges, and the research mainly related to such aspects as the structure selection for and section design of the main girder, the influence of overweight of main girder on the force on the structure, the length of non-cable area of the main girder, the span of auxiliary hole, etc.