In order to investigate the influence of multi-cavity on gas fuel distribution in scramjet combustor, the numerical simulation was used to analyze the pilot hydrogen jet, which was used to pilot kerosene into cold flow in scramjet. The analysis was conducted in three aspects: firstly, dual-cavity combustor with cavities in tandem was compared with single-cavity combustor, with the result showing that the center of hydrogen jet leans to the main stream because of the downstream cavity. Secondly, in dual-cavity combustor with cavities in tandem, upstream cavity was compared with downstream cavity in fuel distribution. The result reveals that hydrogen spreads more extensively in the Z axis direction in upstream cavity, while it spreads wider in Y axis direction in downstream cavity. Finally, the dual-cavity combustor with cavities in parallel was compared with single-cavity combustor. The result indicates that cavity which is in the bottom wall has no influence on gas fuel distribution.