Abstract: The one-key sequence control technology in substations can transform traditional local switching operations into remote one-stop sequential control modes, with significant effects in terms of safety, efficiency, and manpower saving. Therefore, the one-key sequential control renovation project in conventional substations is particularly important. In the process of one key sequential control transformation, the key technical difficulties mainly focus on three aspects: the "double confirmation" of the opening and closing positions of the isolation switch, the electrification transformation of the switchgear handcart and secondary air switch, and the monitoring and management technology of the pressure plate and air switch. This article focuses on these three major technical difficulties and proposes corresponding solutions based on practical experience in renovation projects. It has certain reference value and guiding significance for the one key sequential control renovation of conventional substations.