Rock falling is a threat to the operation of highspeed railways in mountain areas. A comprehensive rockfall protection structure, which consists of anchor frame beam side slope protection and arched opencut tunnel, is proposed for the rockfall protection structure between South Mazongshan tunnel and Qianjiagou tunnel on BaojiLanzhou passengerdedicated railway. The mode of “longitudinal beam + bored pile” is adopted for the foundation of the arched opencut tunnel according to the topographical and geological conditions and the force analysis results. The rationality and safety of the protection structure is verified by finite element numerical simulation on the trajectory and impact energy of the falling rocks and on the structure of the arched opencut tunnel.