The delayed casting technology of wet joints can significantly shorten the construction period of hybrid girder cable-stayed bridges. To ensure the safety of the stress in the cable-girder anchorage structure of the steel anchor box type under this new process, this paper took a large-span hybrid girder cable-stayed bridge as the research object. It studied the stress distribution pattern and the sensitivity of component parameters in the anchorage zone during construction. Firstly, the construction cable forces were obtained by establishing a full-bridge grid model using the finite element software Midas Civil. Combined with the Abaqus software, a detailed local model of the cable-girder anchorage structure was built. Based on the delayed casting technology of wet joints for the hybrid girder cable-stayed bridge, the weld force transfer under different cable force conditions was calculated. Finally, a parameter analysis was conducted considering the variations in the thickness of the anchorage structure plates and the angles of the pre-embedded sleeves. The results indicate that under the delayed two-section casting scheme, the stress in each component of the steel anchor box structure is within safe limits. Influenced by the angle of the pre-embedded sleeves, the stress on the welds tends to be higher on the lower side than on the upper and more significant on the inner side of the bridge centerline than on the outer. The effective stress distribution along the length of the welds typically exhibits a saddle-shaped pattern. The top plate anchor stiffening and the thickness of the pre-embedded sleeves have the most significant impact on weld stress. The maximum weld stress is directly proportional to the horizontal and vertical angles of the pre-embedded sleeves.