The invention relates to a grating type trenchless prop excavating device and a trenchless prop method tunnel excavating process. The grating type trenchless prop excavating device comprises a prop oil cylinder, a hydraulic station of the prop oil cylinder, a concrete pipe, a hoist, outer push iron, a jacket, a guide concrete pipe, a prop stressing device, a grating prop working head or a forwardtype prop working head and a guide rail, wherein the guide rail is arranged under the grating prop working head or the forward type prop working head; the grating prop working head comprises a prop head outer ring, a prop head inner ring and a grating which are welded into a whole; one end surface of the prop head outer ring is provided with a knife edge, and the bottom of the prop head is provided with a translucent window through which the guide rail can pass; and the prop stressing device comprises oil cylinder prop iron, an stressing oil cylinder and piston rod prop iron. The invention issuitable for trenchless excavating tunnels passing through a railway, a highway, an ancient building, a vegetation protecting layer or a rivulet and can effectively control the slide and collapse of the soil layer of an operating surface, reduce the deformation of the surface of the earth and achieve the aim of safe, efficient, civil and environmental-friendly construction.