Light Cycle Oil (LCO) is provided as a by-product of catalytic cracking. Although its volatility and kinematic viscosity is similar to that of diesel gas oil, LCO has lower ignitability. Moreover, it has large amounts of aromatics and contains sulfur as well. These compounds aggravate engine exhaust emissions. However, from the viewpoint of the effective use of fuel resources, the utilization of LCO as fuel for industrial use is desired. Therefore, LCO is mixed with Low Sulfur A Fuel Oil (LSA) which has properties close to gas oil. This paper describes the spray and combustion characteristics of LSA and LCO mixed fuel. In the spray experiments, the spray characteristics were measured by shadowgraph photography and Mie-scattered light photography. In the combustion experiments using a constant volume combustion vessel, the soot formation characteristics were investigated by direct photography. From these experimental results, it was found that the liquid phase penetration is the same regardless of the mixture ratio of LCO, and that the soot formation characteristics can be controlled by changing the mixture ratio of LCO.