An experimental investigation was performed in a 314x25 mm two-dimensional gas-solid fluidized bed with a vertical jet in the center and an inclined jet at the side of the bed, Miller or two kinds of silica sand were used as bed materials in the experiment. The development of the inclined jet was recorded by a video camera. A semi-theoretical correlation was obtained which predicted a jet penetration length which differed from the actual value by at most 25%. When the jet inclination angle was small, by neglecting the influence of the jet position, a simplified equation could be obtained, which differed from the experimental data by at most 40%. A two-phase model was used to simulate macroscopic gas-solid flow in the fluidized beds. The model equations were solved by the improved implicit multifield (IMF) method which can be used for both low and high speed fluid flow. A general-purpose computer program based on the two-phase model was developed. The mechanism of the formation of jets was analyzed by numerical simulation. The influences of jet velocity, nozzle diameter, nozzle inclination angle and nozzle position on the inclined jet penetration length were examined and compared with experimental data. The difference between the horizontal and vertical jets is discussed.