Background: Predatory mites Amblyseius swirskii (Phytoseiidae) was reared on different natural diets to evaluate their value as alternative food source for rearing of this species. Tetranychus urticae kotch (Acari: Tetranchidae) is the mite pests attacking over 1, 100 species of plants in 140 families with economic value. The aim of this study: was evaluated the Physiological effect of feeding on A. swirskii rearing. Using of some artificial diets as an alternative food source for rearing of A. swirskii. Methods: the experiments were carried out under laboratory conditions, at 25 ± 5 ° C and 70% R.H. Most diets reduced the total developmental time of the predator. A. swirskii was feeding on Spider various stages of powder, Cotton Worm Egg Powder, Pollen grains and Bean powder. Results: A. swirskii when fed on Spider various stages of powder, Cotton Worm Egg Powder, Pollen grains and Bean powder the life cycle of A. swirskii were 7.2, 8.2, 7.5and 8.9 days per females but were 6.3, 6.8, 6.9 and 6.9 per males respectively. The life span were 24.4, 20.1, 27.6 and 29.7 in females but were in males 15.5, 16.2, 15.1 and 15.7 respectively. The Chemical analysis of the different foods was 889.6, 826.6, 5.37 and 2.133 total amino acid and was 27.7, 25.6, 698.3 and 2.47 total Proteins.