Studying on the behaviors and mechanisms involving liquid spilling fire is imperative issue in the accident investigations, safety management, risk assessment, and fire analysis of petroleum products. The experimental investigations of spilling fire spread over steady flow n-butanol fuel under different discharge flow rates and spreading directions (opposed and concurrent spreading) were conducted based upon a self-developed laboratory-scale apparatus. Several parameters were revealed to characterize the steady flow fire namely flame brightness, flame height, and relative velocity of spilling fire to flow speed (V-f - u). The fluid dynamic analysis of continuously spilling fuel was performed to find out the relationship of the flow speed and the discharge flow rate. The spilling fires at different flow speeds were separated into four regimes: (I) retardation regime and (II) nonspreading regime in opposed flow, and (III) acceleration regime and (IV) detachment regime in concurrent flow. The parametric variation and the inherent mechanism were discussed to reveal the effects of the discharge flow rate and spreading direction on the liquid spilling fire. The findings of the present research are beneficial for the development of the fuel spilling fire protection measures.