Multi-dimensional simulation was conducted on a small high intensified diesel engine. The influence mechanism of the interaction of intake swirl and spray angle on the in-cylinder mixture distribution, fuel evaporation, mixing and heat release processes was analyzed. Optimum matching criteria was finally acquired. The results showed that increasing and decreasing the intake swirl and spray angle could accelerate the fuel evaporation rate before and after TDC respectively. Swirl could accelerate the process of mixing fuel and air, but if spray angle was too large, the mixing rate in the later part of injection could be retarded. When the swirl ratio and spray angle were matched appropriately, the mixture would be more uniform and the SMD would be smaller, which could significantly optimize the premixed combustion process.