To investigate the influence of cylindrical charge geometry on blast load distribution under internal explosion conditions， 16 numerical models were developed using LS-DYNA following experimental validation. A comprehensive parametric study was conducted to systematically evaluate the effects of three key factors： charge length-to-diameter ratio （L/D=1-5）， ignition location （head， center， tail）， and charge orientation. The analysis compared overpressure contours， reflected overpressure-time histories， impulse-time histories， and peak values across different scenarios. The results indicate that the L/D ratio exhibits the most significant impact on blast load distribution. As L/D increases from 1 to 5， the reflected overpressure ratio decreases dramatically from 37.5%-1287.9% to 25.5%-356.7%， and the reflected impulse ratio reduces from 88.7%-235.3% to 76.5%-132.8%. The effect of ignition position is region-specific， with the maximum differences in reflected overpressure and impulse ratios reaching 2173.3% and 328.0%. Charge orientation influence diminishes with increasing L/D ratio and incidence angle. Specifically， when L/D ratio increase from 1 to 5， the maximum reflected overpressure ratio decreases from 1287.9% to 356.8%， and impulse ratio decreases from 235.3% to 132.7%. The distribution of internal blast loads is primarily governed by the L/D ratio， followed by charge orientation and ignition location.