This study took maize as an example and designed a new system for synchronous collection of hydrophobic root exudates from multiple varieties of maize. The new collection system includes a new maize cultivation device and corresponding collection methods. The main body of the cultivation device consists of a fixed plate and a water storage tank. Maize grows vertically inside the fixing plate, and moisture is provided by the moist filter paper inside the plate. The root exudates of maize in the board are collected by rinsing or soaking the roots after 12 days of cultivation. Compared to the traditional hydroponic collection methods, this new synchronous collection system can not only significantly improve the biological nitrification inhibition (BNI) activity of root exudates, but also significantly save 88% of collection space, 99% of nutrient solution usage, and 94% of manpower. The root exudates of 10 typical maize varieties collected synchronously through this system showed significant BNI activity, with an average of 55%, and more than half of the varieties had an inhibition rate of over 50%. There were also significant differences among different corn varieties, with the inhibition rates of Xianyu 335 and Zhengdan 958 exceeding 75%, while Jidan 33, Jinyu 188, Ruipu 909 and Beiyu 851 had inhibition of around 30% - 40%. The experimental results of two batches had good reproducibility. These results indicated that the new system can be used for synchronous collection of hydrophobic root exudates from multiple varieties of dryland crops, and can be applied in the identification of maize BNI and analysis of BNI genetic locus.