Under compressive loading, rocks emit electromagnetic waves, and monitoring electromagnetic signals has become a key means of predicting dynamic rock disasters. To understand how dynamic potential is generated in rocks under compressive loading, the relationship between the compressive loading (P) and the stimulated potential (E) is seen as a circuit system (H(t)). A circuit analysis model has been established to study how rock particles restructure under compressive loading. Experimental tests were conducted to measure the input excitation (E) and output response (U_σ(t)) or (I_σ(t)) of the rock specimens, with four types of rocks being tested. The experiments revealed that voltage, current, frequency, and impedance changed during the particle reorganization process under compressive loading, showing that the electromagnetic radiation of the rock specimens mainly came from the current generated by the internal particle reorganization. The intensity of electromagnetic radiation was found to depend on the load size and dynamic impedance (Z_σ), with the dynamic impedance (Z_σ) consisting of the microelement total resistance (R_σ), capacitance (C_σ), and inductance (L_σ). The variation of dynamic impedance (Z_σ) is related to the rock type. The research findings have contributed to elucidating the mechanism of electromagnetic radiation generated by rocks under load.