Two field experiments were carried out during two successive seasons of 2017 and 2018 at the Experimental Farm of Kaha Station, Qalubia Governorate, Egypt. The study investigated the effect of three irrigation levels (50%, 75% and 100%) from crop evapotraspiration (ETc) and five foliar spraytreatments by aqueous extract of date palm pollen grains at 1, 3 and 5 g/l, lithovit at 1 g/l and tap water (control) on common bean plants c.v.Nebraska. The effect of treatments on growth, seed yield, chemical characters as well as water use efficiency were studied. The recorded results illustrated that the plants sprayed by date palm pollen grains extract at 5 g/l and irrigated by 100% (968.72 m³ water/fad.) or 75% (726.54 m³ water/fad.) of irrigation water, gave the highest values of all vegetative growthparameters. On the other hand, the plants sprayed with date palm pollen grains extract at 1, 3 or 5 g/l followed by lithovit at 1 g/l, respectively and irrigated by 100% or 75% of irrigation water gave the highest value for each of number of pods/plant, weight of 1000 seeds and total dry seed yield ton/fad., compared to the control, i.e. water foliar spray treatment in both growing seasons. Water use efficiency (WUE) decreased when the amount of irrigation water increased to 100% ETc and the highest values were obtained from 50% treatment followed by 75% Etc. Moreover, the plants sprayed with date palm pollen grains extract at 5, 3 or 1 g/l, respectively,followed by lithovit at 1 g/L (nano-fertilizer) showed the highest values of WUE. Generally, it can recommend by spraying common bean plants by date palm pollen grains extract at (5, 3 or 1 g/l)respectively,followed by lithovit at 1 g/l (nano-fertilizer) with irrigation at level of 75% from ETc to obtain the highest seed yield with the best quality and the favorable water use efficiency at the same time saving 25% from water irrigation quantity.