Although partial ground-anchored suspension bridges provide economical and feasible technical solutions when constructing ground suspension bridges under soft-soil geological conditions, the main girder bears a relatively large stress under anchor force. In this paper, analyzing the specific steel box composite beam with the Ultra-High-Performance Concrete (UHPC) bridge deck, we investigate the adaptive capacity of the main beam of the partially ground-anchored suspension bridge. Through the analysis of ground anchor forces, the maximum ground anchor force within the allowable stress range of the pavement layer is de-termined. This provides a basis for determining the corresponding cable forces, anchor forces, and anchor dimensions, offering valuable insights for the design of partially ground-anchored suspension bridges.