The preparation, manipulation and detection of single particles represent one of the key research directions in the development of experimental physics. As the core objective of next-generation ion beam technology, the deterministic generation and nanoscale positioning of single ions can break through the technical limitations of on-demand extraction in conventional ion sources, providing critical technical support for the advancement of cutting-edge fields such as quantum technology and atomic-scale manufacturing. This paper reports on a deterministic single-ion source technique based on time-correlated measurements. By exploiting the time correlation between electron-ion pairs generated by photoionization of cold atoms in a magneto-optical trap, and using coincidence measurement where electrons serve as a trigger signal to control the ion trajectory, the technique achieves the deterministic preparation of a high-fidelity single-ion source. We characterize the ion source performance in both continuous-flow mode and single-ion mode: in continuous-flow mode, the electron and ion counting rates are 4.9×10³ s^–1 and 4.9×10⁴ s^–1, respectively. In single-ion mode, the maximum electron-ion coincidence rate is 53.5%, and the single-ion fidelity is 80.1%. The results of single-ion focusing imaging and numerical simulations based on experimental parameters indicate that the emittance of the deterministic single-ion source is (1.01±0.06)×10^–10 m·rad·eV^1/2, and the brightness is (7.2±0.8)×10² A·m^–2·Sr^–1·eV^–1, meeting the requirements for the development of deterministic single-ion nanobeam technology. This approach offers excellent scalability in terms of ion species and single-ion manipulation. On the one hand, the method is applicable to all atomic systems that can be laser-cooled; on the other hand, by combining dynamic lens electric fields with electron-ion momentum correlation control, it is expected to enable ion beam aberration correction and spot optimization, further enhancing its overall performance. Therefore, this deterministic single-ion source holds broad application prospects in cutting-edge fields such as ion microscopy and high-precision single-ion implantation.