Underwater active electric field detection is an important sensing technology applicable to turbid waters, low-light conditions, and other complex marine environments. Traditional low-frequency electric field sources usually adopt discrete paired electrode structures, and the large system size not only restricts the flexibility of deployment in narrow spaces but is also easily affected by environmental factors such as water disturbances, thereby reducing the stability and accuracy of detection. The emerging solution integrates the source electrodes in the single structure to achieve a compact design with miniaturization advantages, providing a solution to improve system integration and detection performance. In this paper, modeling and simulation studies are conducted on the underwater active electric field detection method. The theoretical model of the electric field generated by the compact electrode structure is established, the perturbation characteristics of typical underwater targets on the electric field distribution are analyzed, and the corresponding simulation model is constructed. The simulation results demonstrate that the compact electrode structure can effectively generate low-frequency electric fields and facilitate target detection. Furthermore, the influence of some structural parameters on detection performance is analyzed.