Magnetic resonance spectroscopy is one of the most powerful spectroscopic tools for obtaining detailed information about molecular structure. It has also served as a remarkable tool for exploring quantum phenomena in large spin ensembles. The electronic spin ensemble corresponding to diamond defects can be manipulated and characterized by Electron Paramagnetic Resonance (EPR), while the lack of fully understand the magnetic resonance spectrum has motivated a simulation of the electronic system. Dipolar coupled spin-1/2 particles in diamonds form a prototypical many-body system and indeed many-body effects could be observed in magnetic resonance spectroscopy. We simulated many-body resonance spectrum of dipolar coupled electronic system to explore the impact of different conditions on EPR spectroscopy, and then obtained an insight of Hamiltonian and energy levels change of the system in magnetic field. Our simulation reveals the relationship between the spectrum line-width and electronic structure density and location homogeneity in diamond. Our work paves a way to better understanding of many-body resonance of electronic dipolar coupling system.