Abstract. This paper proposes a method for acquiring complete status information and data from the marine controlled-source electromagnetic (MCSEM) transmitter during offshore experiments. The subordinate machine system is constructed on the STM32 platform and incorporates a real-time operating system. It utilizes the internet of things (IoT) concept to interconnect various modules within the transmitter, enabling intelligent control and management. At the same time, data are uploaded to the control room on the deck through photoelectric composite cables, and the host computer's software, designed with Python language, will process and store all the data. This allows workers on the deck to control the subordinate computer and obtain high-precision, complete data in real time. The joint tests between the subordinate and host computers have demonstrated the stability and reliability of the online transmitter system, which provides significant convenience for offshore exploration.