To estimate plasma parameters in a dielectric barrier discharge (DBD)-based single barrier capillary source, a spatio-temporal plasma spectroscopy and a particle-in-cell simulation code OOPIC-Pro has been used. The developed DBD source consists of a 10-cm length capillary source with diagonally opposite striped electrodes pasted on the cylindrically hollow quartz tube of 4-mm outer and 2-mm inner diameters, respectively. The plasma has been produced in helium atmosphere using pulsed power source with 2-5 kV, 30-kHz square pulse having pulsewidth (2μ) s at different operating pressures. For space resolved plasma diagnostic, a high-resolution intensified charge coupled device camera has been used. The images of the discharge patterns of this pulsed DBD source have been compared with the simulation results and certain useful discharge parameters have been obtained. The obtained electron density in plasma from simulation has been compared with discharge resistivity method, which is found to be in close agreement. The filamentary and diffused discharge patterns have also been analyzed based on the electrical discharge patterns obtained from the simulation, which provides additional insight in such narrow DBD discharges. © 2014 IEEE.