Abstract: According to the characteristics of the high-speed camera trigger mode, a new method of controllable self-triggered arc image acquisition was proposed based on electrical signal monitoring. The system's hardware platform composition and software framework were introduced. The shooting trigger algorithm based on the root mean square value of electric signal as the monitoring condition was discussed, and the specific implementation method of synchronous collection of the electric signal and the arc image were described. The arc image acquisition system was verified by the welding experiment of the specimen with a greasy surface. The experiment showed that the system could effectively and reliably trigger high-speed camera shooting based on electrical signals and capture the transition process information of the greasy surface. Finally, compared with the normal process, the transition period was obviously increased when it was the greasy surface, and the arc was more diffused.