Computational Fluid Dynamics (CFD) analysis using the Volume of Fluid (VOF) method was conducted to study the behavior and atomization of a liquid sheet sandwiched by air jets from rectangular nozzles, which is the simplest model of a filming type air-blast fuel nozzle for aero engines. Effects of ambient pressures of 0.1 and 0.8 MPa, strength of shear of air jets by different vane angles of zero and 45 degrees on the behavior and atomization of the liquid sheet were investigated. The behavior of the sheet predicted agrees with that observed in the experiments using a 2-dimentional air-blast nozzle. No effects of ambient pressure or strength of shear on SMD were predicted while the SMD is independent of strength of shear at atmospheric pressure but becomes smaller at the stronger shear conditions. Inaccuracy of the value of surface tension used in CFD is thought to be one of the major reasons for the inconsistency in the values of SMD by CFD prediction and experiment.