Abstract: As a common fieldbus technology, ProfiBus fieldbus has been widely used in the field of industrial automation. With the continuous developments of science and technology, industrial production, including the field of offshore oil drilling, is becoming more and more intelligent and automatic. Today, the mainstream oil drilling platform has achieved high automation. This paper briefly describes the application of ProfiBus fieldbus technology in offshore oil drilling platform, and takes a ProfiBus communication failure in the top drive control system of Kantan 7 jack-up offshore oil drilling rig as an example to explain the fault phenomenon, analyze the cause of the fault and the troubleshooting method. The purpose is to provide reference for the failure prevention, failure cause analysis, failure search and elimination of similar equipment in the operation of highly automated offshore oil drilling platform in the future.