Irrigation water is considering important single attributes of sustainable rice production; more effectiveness water management system is required for agriculture. So, the management of water Utilizing in rice producing systems is necessary to increased productivity. Current study was carried out in the trial farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt, in the summers of 2019 and 2020, to determine the outcome of plant spacing (15x20, 20x20 and 25x20 cm) on growth, grain yield and water use efficiency of two inbred rice cultivated variety (Giza 179 and Sakha 106) under varying times between irrigations namely, continuous flooding (CF), six-day irrigation intervals (6D) and 12-day irrigation intervals (12 D). A strip - split plot design was applied, with four replications. Obtained results revealed that as irrigation intervals increased to as many as twelve days, there were considerable decline in growth characteristics, grain yield and its traits without any significant variations between Cf and 6D in grain production in both seasons. Giza 179 rice variety significantly surpassed Sakha 106 rice variety for growth (Dry matter content and leaf area index “LAI") and grain characteristics (No. of panicles per m2 as well as total grains per panicle, panicle length, panicle weight, grain yield and straw yield per ha), excluding the 1000 grains weight, which was the greatest values with Sakha 106. Grain yield was significantly larger at closer plant spacing of 15x20 cm than at wider plant spacing of 25x20 cm.