A method for constructing a large-span station by two-wing open type semi-covered excavation and semi-reverse construction, is divided into three stages of excavation. First, excavate a first-stage inner small foundation pit, then excavate a second-stage annular foundation pit within the first-stage retaining piles and outside the range of the first-stage inner small foundation pit, and finally excavate a third-stage semi-covered excavation foundation pit below the first-stage inner small foundation pit and the second-stage annular foundation pit. By setting graded retaining piles, middle upright post piles, middle top plates, local waist beams and local concrete supports in the soil-rock combination strata, so that the force transfer between the foundation pit enclosure and the station main body structures and the underlying rock layer is clear and reliable, and a stable frame structure is achieved.