A great number of electromagnetic abnormal phenomenon before or after earthquakes were recorded by electromagnetic instruments ACF-4M.These instruments have been installed at ELF (extremely low frequency) stations built in the 10th "Five-year Plan" period.With the development of urbanization, many observation sites cannot meet the requirements of electromagnetic observations; therefore, unattended stations with low electromagnetic background noise are needed.However, the measurement system did not achieve the required automation.This study introduces the remote control and data transmission of ELF instruments and the development plan of the original data transformation.As the ELF recorder cannot access the Internet, it is necessary to have intermediate equipment to remotely trigger the ELF instrument.The remote computer controls the local area network's computing terminal through the Internet, and subsequently through the terminal corresponding programs run to realize data transmission.The ELF instrument can improve the application efficiency of observation data and speed up the use efficiency of electromagnetic data.