The aim of this research is to study the optimal time for irrigation, estimate water requirements of maize using visible laser and calculate water use efficiency to irrigate Nile maize crop. The experimental and field setups were carried out at the Institute of Laser Enhanced Science (NILES) and Farm of the Faculty of Agriculture, Cairo University, Giza, Egypt. Maize crop (11 hybrid variety) was used in the planting during autumn season of 2012, under the furrow and drip irrigation systems. Also two water regimes used soil moisture depletion (S.M.D) and evapotranspiration of crop (ETc) with three levels of water (10,25 and 50% for S.M.D and 1.25, 1 and 0.75 for Etc). In the meantime the ETc was calculated using CROPWAT program. The experimental setup of laser beam transmission (LBT) measures transmission light through maize leaves considering the moisture content in the canopy leaf for different plants. The obtained results were as follows: 1) The values of laser beam transmission increased by decreasing of the SMD to the best time to irrigate according to use of LBT within range between 30 to 35 mV at water regimes 10% of SMD and 1.25 ETc, 2) The crop water use efficiency (CWUE) was 1.40 and 1.66 kg/m3 under furrow and drip irrigation systems with fully irrigation regimes, while, the traditional methods of furrow irrigation gave low CWUE ( 1.0 kg/m3), and 3) The crop yield increased 856.70 and 531.57 kg/fed, with water saving of 167 and 40 m3/fed for drip and furrow irrigation systems at 10% SMD respectively, compared with traditional furrow method.