The vaporization and combustion of liquid spray in a cylindrical shape combustor was studied numerically. Mixture of liquid drops and air was assumed to be ejected from the center-hold and assisting air from the concentric annulus with swirling. Eulerian-Lagrangian scheme was adopted for the two phase calculation, and the interactions between the phases were considered with the PSIC model. Also adopted were the infinite conductivity model for drop vaporization, the equation of Arrhenius and the eddy break-up model for reaction rate, and the k-ε model for turbulence calculations. Gas flow patterns, drop trajectories and contours of temperature and mass fractions of the gas species were predicted with swirl number. drop diameter, and equivalence ratio taken as parameters. Calculations show that the vaporization and the consequent combustion efficiency enhance with the increase of the swirl number and/or with the decrease of drop size, and the higher maximum temperature is attained with the higher equivalence ratio.