The experiments were carried out at ABED*, FAMU** and connecting with ARI, ARC*** Dokki, Giza, Egypt to study effect of microwave drying on onion quality and properties at 2018. The following points will be considered: microwave power levels and onion slices thickness, fitting the mathematical models (Lewis's model) which describe the microwave drying curves. At 640W and thickness of 6mm are consider the olmost good treatment for dryer using microwave at 19°of Hue angle(H),considered the best method of drying onion because it was given the lowest value of total color change.