In order to solve the problem of current measurement in vehicle microgrid with rich current frequency components and complex electromagnetic environment, a new closed current measurement method is proposed, which is based on the advantages of low frequency characteristics of tunnel reluctance sensor and high frequency characteristics of rogowski coil. Ansoft Maxwell is used to simulate and analyze the shielding effectiveness of the shielding shell. The power frequency measurement experiment is carried out with Rogowski coil and tunnel magnetoresistance sensor, and the calibration is completed with the clamp current probe as the benchmark. The calibration parameters are applied to the peak pulse current measurement in the process of micro grid parallel and off grid, and the data composite processing is carried out. The experimental results show that the composite current measurement signal is in good agreement with the clamp current probe signal, especially performs as the reduction of the peak error, and the relative error of the composite peak pulse current is reduced to 3. 67%. The current measurement method based on the data combination of rogowski coil and tunnel magnetoresistance is of great significance for the electrical measurement of equipment.