[Purpose/significance] The study aims to seek inspirations for building up remedy mechanism to prevent patent defects by delving into the patent information system of Japan.[Method/process] The researcher interprets the content of Japanese Third-party Observation System, assessed its performance, and investigated its functional changes.[Result/conclusion] The Third-party Observation System of Japan undoubtedly provides the public with a zero-cost channel to check the patent defects. It enables the examiners to access relevant information before the patent is granted, so that effective and accurate patent examination can be achieved; moreover, it is a critical approach to collect patent information of patent right after the patent is granted. The system can offer some guidance for improving public involvement of Chinese patent examination, especially for the content, the method and the feedback mechanism.