Abstract: The effects of partial root-zone drought stress on root growth in maize were studied in split-root and solution culture experiments. Sub-root samples were scanned for root length and area using CI-400 computer image analysis system (CID Ltd, USA). Maize plants were subjected to water stress by regulating the osmotic potential of the solution using polyethylene glycol (PEG-6000) in the experiment. Water was supplied at four levels - CK (sufficient water supply), 0.2 MPa (low water stress), 0.4 MPa (medium water stress) and 0.6 MPa (high water stress) for 6 days. After that, the roots were divided into two parts, one part was re-watered, and the other part was imposed continuously four water supply levels - over eight time periods - 0 h, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d and 9 d. Compared with CK, growth of the re-watered roots part significantly increased after drought stress. While the re-watered half was larger than the stressed half of the root, the total root length was not significantly different under different water stress treatments. The increasing strength of the re-watered half of the root at the four different levels was different. The order of strength for the treatments was CK > 0.2 MPa > 0.4 MPa > 0.6 MPa. After preprocessing stage of total root osmotic stress, both sides of the root showed signs of water stress. Root length, area and dry weight in the re-watered root-zone and total root length and area of plant in the 0.2 MPa treatment were either close to or higher than the control treatment. Water absorption of the root system was influenced by re-watering after root-zone drought stress, which was compensated for root growth. Appropriate drought stress increased root area, but did not significantly increase total root length and dry root weight. Under the experimental conditions, the compensation effects of maize root system were related to the degree and time of drought stress.