In this experiment,two varieties of Eruca sativa Millcultivated in substrate culture were used to study the effects of different harvest times on the matter accumulation and nutritional quality of the plant.This was done through measuring the chlorophyll content,root activity,nitrate content,nitrate reductase activity,fresh weight and dry weight of a single plant and relating the resulting data to the plants nutrient content.The results showed that in both varieties of Eruca sativa the matter accumulation,sucrose content,reducing sugar content,Vc content and soluble protein content were higher and the nitrate content was lower at treatment IV(45 days after emergence)and treatment V(50 days after emergence),so it may be concluded that these are the optimal harvest times for Eruca sativa Mill..