A structure of material feeding device is provided for avoiding material obstruction. In the material feeding system, a motor is adopted to drive material feeding member to spin in a material feeding silo. By using mechanical stirs, the blocking phenomenon of material is mitigated and thus achieving the purpose of avoiding material obstruction. According to the present invention, the first material feeding silo is connected with a first screw feeder for conveying materials. The first screw feeder is also connected to a second material feeding silo. The second material feeding silo is connected with a pipe. The pipe includes a first sealing valve and a second sealing valve for keeping the pipe sealed and thus avoiding contamination. Finally, the pipe is connected with a second screw feeder, which feeds materials into a vessel. Then a complete conveying line is formed for facilitating industrial production.