It is important to study crop water requirement rule for water-saving irrigation and water regulation management of dry land crops in arid and semi-arid regions. In this study, the maize water requirement was estimated by means of McCloud model and Penman-Monteith model, and the amount of irrigation water in maize field was estimated by water balance approach in Songnen Plain,NE China. The main results are shown below : ( 1 ) both in historical period and projected climate change scenario, the maize irrigation water amount contour lines during the whole growth period and L_(mid) periods decreased along southwest to northeast geographically, and the same irrigation water amount contour line moved north with the progression of decades. Compared with 1970s, the zero equipotential line of irrigation water requirement during the whole growth period and L_(mid) period in 2000s moved to north by 70.2 km and 53.4 km, respectively. Compared with 2010s, the zero equipotential line of irrigation water requirement during the whole growth and L_(mid) periods in 2040s moved to north by 30.9 km and 55.2 km, respectively. (2) The maize irrigation water requirement during the whole growth period increased volatility coupled with the progression of decades both in historical conditions and in projected climate change scenarios, and the rate of the increase was 29.1 mm/( 10a) in historical period and 17.5 mm/( 10a) in projected climate change scenarios. (3) Compared with 1970s, contribution of climate change to the maize irrigation water requirement was 22.1% in 2000s and 38.3% in 2040s, namely an increase of 6.8* 10~8 m~3 in irrigation water requirement in 2000s and an increase of 12.6* 10~8 m~3 in irrigation water requirement in 2040s.