The cladding surface of the substrate was fixed at an upward angle which was greater than 90° in relative with the horizontal surface, where the single cladding tracks were formed by the laser inside powder feeding technology. The relationship among the tilted angle of the powder feeding nozzle, the pressure of the protection air and the powder spot diameter at the working plane were studied based on the experimental data. The effect of laser power and scanning velocity on the height and width of the tracks was analyzed, while the powder feeding rate and defocus amount kept unchanged. The liquid molten pool tended to drop by the drag force of its gravity, and the height peak offset was also studied. With the increase of the titled upward angle, the powder spot size at the working plane became larger, while the pressure of the protection air did the other way. For upward cladding, the effect of process parameters on the width and height shows a good accordance with the horizontal cladding. However, the height of the cladding layer was dramatically affected by the laser power, scanning speed and the tilted angle. The peak height offset of the molten pool got smaller with the decrease of the power and increase of the scanning speed and tilted angle. By using the optimized process parameters and the proper protection air pressure, a 3D part with the maximum titled angle of 150° was formed which also had the good feature accuracy and fine microstructure.