Abstract: To comprehend the water balance condition of corn and soybean crops during the growth period in Liaoning Province, based on the daily meteorological data and crop coefficients from 1963 to 2022 in Liaoning Province, the SIMETAW model and the climate diagnostic analysis approach were used to analyze the precipitation and water demand patterns as well as the water supply circumstances of corn and soybean crops during the growth period in Liaoning Province, uncover the influence of regional climate change on the water requirements of corn and soybean crops, and investigate the spatial and temporal evolution of effective precipitation and water demand for corn and soybean crops in Liaoning Province. The results show that the effective precipitation for crops throughout the growth period in Liaoning Province amounts to 481.6 mm, among which the western region is 347.4 mm, the central and southern regions are 514.9 mm, and the eastern region is 636.8 mm. The average water demand for corn and soybean crops throughout the growth period is 521.0 mm and 517.0 mm respectively. There is no conspicuous downward trend. The coupling degree between precipitation and water demand for corn and soybean crops throughout the growth period is 0.822 and 0.815 respectively, signifying that precipitation can fulfill more than 80% of the water demand, with an average deficit of 17.8%～18.5%. The maximum coupling degree occurs in the eastern region of Liaoning Province, followed by the central and southern regions, and the minimum value emerges in the western region of Liaoning Province. The guarantee rate of the coupling degree λ＞0.8 for corn and soybean crops in the western region of Liaoning Province is merely 28.3% and 21.5% respectively.The highest value of the coupling degree appears in the middle growth stage, followed by the rapid growth stage, and the lowest value emerges in the early growth stage and maturity stage. In recent years, the coupling degree of precipitation and water demand in the early growth stage of corn has demonstrated a notable upward tendency. The coupling degree between precipitation and water demand in the early growth stage of corn and soybean in Liaoning Province is relatively low. Thus, it is essential to pay attention to the occurrence of spring drought, particularly the water shortage situation in western Liaoning Province.