The bubble defects of glass products not only affect its performance, but also impact their appearance and application. These defects depend upon glass formula, batch ingredients, melting process, and also the improper operation in the spout system. In the paper, the spout system, preparation of orifice and the replacement of spout were discussed in detail, and then the bubble defects caused possibly by the improper operation was set forth from the view point of glass technology. Finally, the characteristics of common bubble defects in the feeding system were summarized, and the precautions and solutions were proposed for reference.