109Ag is located on the pathway of the slow neutron capture process, and 79% of 109Ag is generated through a rapid neutron capture process. Meanwhile, the mass fraction of 109Ag in Ag-In-Cd control rods is 38.56%. Therefore, the neutron capture cross-section of 109Ag is crucial for both nuclear energy and nuclear astrophysics applications. In this work, a neutron capture cross-section is measured using a 109Ag isotope target at the Back-n white neutron facility of the China Spallation Neutron Source (CSNS). Neutron capture cross-sections in the 1–500 eV energy region are obtained by combining the time-of-flight method and the pulse-height weighting technique. The 109Ag resonance energy, neutron resonance width, and gamma resonance width parameters are extracted using the SAMMY code, which is based on R-matrix theory. The neutron resonance parameters extracted from this study at 139.4 eV are in agreement with the values evaluated in the JENDL-4.0, while the parameters at 169.9 eV and 328.1 eV are in agreement with the values evaluated in the JEFF-4.0. Additionally, the result at 259.3 eV is consistent with the value evaluated in the CENDL-3.2.