The invention discloses a pure wood ceiling system, which comprises ring fastening pieces I (2), U-shaped hanging pieces I (4), a square pipe (6), cross connecting pieces (7), transverse square pipes (8), ring fastening pieces II (9) and lead screws (11), wherein the ring fastening pieces I (2) fasten a pure wood top wooden beam (1) and are fixed through bolts I (3), the U-shaped hanging pieces I (4) are fixedly connected with the ring fastening pieces I (2) through bolts II (5), and the square pipe (6) is installed in the U-shaped hanging pieces (4); the cross connecting pieces (7) are arranged on the square pipe (6), and the transverse square pipes (8) are connected to the square pipe (6) through the cross connecting pieces (7); and the ring fastening pieces II (9) are arranged on the transverse square pipes (8), 7-shaped hanging pieces (10) are arranged on the ring fastening pieces II (9), and the leads screws (11) are arranged on the 7-shaped hanging pieces (10). The pure wood ceiling system has the advantages the pure wood top beam can be prevented from being damaged and the installation of a ceiling through a stress bed frame is realized.