This work verifies the neutron flux for a modified zero-power-reactor facility using neutron activation. Ten foils are activated and counted to illustrate the precise neutron spectrum at a particular location inside the reactor core through the computerized software Spectrum Analysis by Neutron Detector-II (SAND-II). In addition, neutron spectra derived from 11 different locations are compared with the computational results from the WIMS reactor analytical software, respectively, and then the neutron distribution with various energy groups inside the reactor core is rearranged. A quantified index, AT, is also introduced to compare the experimental and computational results. In this work, the ATs are evaluated as 2.28 ± 0.48, which implies a slight discrepancy between the computational and experimental results. Moreover, a softer neutron spectrum evaluated by the WIMS calculation is verified by further examining the experimental data. Recommendations on how to apply the WIMS calculations are also offered.