Abstract: Abstract: In order to prevent agricultural droughts in the future, a dynamic monitoring system for the drought transition process of the spring maize in the Northeast of China (NC) in 2018 was established to track and get feedback of the temporal spatial characteristics of droughts using the crop water deficit index (CWDI) method. A meteorological interpolation software, ANUSPLIN was used to interpolate the daily average temperature, the maximum temperature, the minimum temperature, the average wind speed, the average air pressure, sunshine hours, the average relative humidity and the precipitation data at meteorological stations in NC in 2018. These meteorological data can be extended from some points to the surfaces. The daily pixel-by-pixel reference evapotranspiration (ET0) of crops was calculated by programming in IDL language. The maize characteristics were determined at the different growth period, including the early, middle and late stages. Using the Kriging method, the key growth data of maize were interpolated at the growth period including seeding, three leaf, tasseling, milking, raping. The daily maize crop coefficient and dynamic thresholds was improved by using the key growth data and function to cumulative improved CWDI. Then daily and 8-day synthesis of CWDI and improved CWDI were calculated. The improved CWDI monitoring data of the spring maize at the drought in 2018 were in good agreement with the survey data of the ground drought, with the high accuracy of 75.7%, which is 8.1% higher than CWDI. Improved CWDI has shown good spatial continuity, which is suitable for the purpose of dynamic monitoring of the drought disaster process of spring maize. In 2018, the spring drought in NC was stronger than the summer drought, while the drought degree was more serious during the maize growing period. Both the spring drought and summer drought occurred in NC in 2018, particularly the most severe period occurred in May and from late July to mid-August. The area of spring drought was larger than that of the summer drought. The spring drought mainly occurred in the western and northern of Liaoning Province, western Jilin Province, Chifeng and Tongliao in Inner Mongolia. The spring drought began to occur in the west of Jilin Province and expanded continuously to the southwest, with the direction of subsidence consistent with the direction of movement. The summer drought mainly occurred in the south of NC, particularly in Liaoning Province. The drought continued to develop from the eastern part of Inner Mongolia and the western part of Liaoning Province to the eastern part, and then decrease from the eastern and western sides to the central part. In the whole growth period of maize, the drought occurred to a certain extent. The improved CWDI can well reveal the mitigation effect of the precipitation process on drought before and after May 22, 2018. The improved CWDI can be used to monitor the drought disaster process of the spring maize in NC. It was also sensitive to the short-term variation of precipitation factors. The change of drought intensity that caused by increasing daily precipitation can also be represented in real time.