The velocity of the flyer is a key factor in determining the reliability of initiating exploding detonators. In order to investigate the influence of barrel parameters on the flyer velocity， the factors affecting the flyer velocity were analyzed through both experimental and numerical simulation methods. A TiW/Ni/Au composite film exploding foil with a film thickness of 0.5/0.5/2 μm and dimensions of 0.15 mm×0.15 mm was designed and prepared using magnetron sputtering technology. Under excitation conditions of 0.1 μF and 1200 V， a polyimide flyer with a density of 1.45 g·cm^-3 and a thickness of 25 μm was selected， and the flyer velocities with different barrel parameters were measured using photon Doppler velocity testing technology. The research results indicate that， under the same diameter conditions， the flyer velocity initially increases and then decreases with increasing barrel thickness， reaching a peak at 0.4 mm. When the barrel diameter are 0.15， 0.23， 0.3， 0.35， 0.45 mm， the flyer velocity decreases as the diameter increases， with the highest velocity observed at a diameter of 0.15 mm. Furthermore， under the same thickness and diameter conditions， the velocities obtained from polyimide and ceramic barrel tests exhibit similar trends and values， with polyimide demonstrating higher strength and toughness and lower cost， making it a viable alternative to ceramic as a barrel material. Furthermore， a numerical simulation method was used to re-fit the empirical formula for flyer velocity applicable to the TiW/Ni/Au composite thin film， and the verification results show that the deviation between the calculated results and experimental data is within 2.5%.