By designing pulsed receiving antennas and optimizing test methods, the relationship between laser parameters, such as intensity distribution of electromagnetic pulses (EMPs) from SGIII prototype laser facility and target type is established, which can provide an experimental basis for further investigating EMP generation mechanism and laser-target interaction. Based on the consideration of the polarization direction uncertainty of electromagnetic fields, three mutual orthogonal magnetic loop antennas are selected to measure the EMP signal inside the target chamber of the laser facility. A comparative analysis on the frequency features of the EMP signals from two kinds of targets is conducted, and the influence of antenna position on the signal strength is discussed. At the same time, the distribution of EMPs inside the spherical chamber is analyzed by multi-physics simulation.