SOFC/GT hybrid system is proposed as one of the advanced power systems of future ships due to its high efficiency, low emission and fuel flexibility. However, how to efficiently reform marine diesel into H2 is the key to maintaining the operation of SOFC/GT. This paper studies the influence of operating parameters such as S/C, temperature and pressure of ship SOFC/GT hybrid system on H2 production characteristics of marine diesel reforming through numerical simulation and experimental analysis. The results show that under the variable working conditions, the H2 production increases with temperature and the carbon deposition decreases. The increase of S/C promotes the increase of H2 yield and inhibits carbon deposition. Pressure has a negative effect on H2 production. The research results can provide basic technical support for the safe and efficient operation of the SOFC-GT hybrid power system on ships and the continuous supply of fuel.