The process of lateral seepage constitutes a crucial component of the water cycle in paddy fields. Previous studies have focused on the effects of control regulation field water layer management on lateral seepage in paddy fields. However, less attention has been paid to the lateral seepage of paddy field water under controlled irrigation, and there is a paucity of research findings regarding seepage in paddy fields under coupled controlled drainage. In order to optimize the water management of paddy field, a two-year in-situ field test was conducted, and diverse irrigation and drainage treatments were implemented. The characteristics of lateral seepage in paddy fields subjected to controlled irrigation and drainage regulation were systematically analyzed, and the response mechanism of lateral seepage to such control regulation was revealed. The findings were as follows: compared with free drainage, controlled drainage inhibited the change of soil moisture content in the field bund. Compared with flooding irrigation, the fluctuation of soil moisture content in the field bund under controlled irrigation field bund was more intense. Controlled irrigation and drainage regulation had a direct impact on the characteristics of lateral seepage in the field bund canal transition zone, and significantly reduced the total amount of lateral seepage. Controlled irrigation and drainage, as opposed to flooding irrigation and free drainage, respectively reduced the peak and mean values of lateral seepage intensity, and significantly reduced the total amount of lateral seepage in the paddy field, during the two-year experiment period, the controlled irrigation and drainage treatment of the rice fields resulted in a reduction of 63.49% compared with the free irrigation approach. Both paddy field irrigation and drainage treatments exerted a considerable influence on lateral seepage intensity, with irrigation treatments demonstrating a stronger effect. Paddy field irrigation treatment and drainage treatment had a significant effect on the lateral seepage intensity, and the effect of irrigation treatment was stronger. Compared with flooding irrigation, controlled irrigation significantly increased the proportion of water seeping from the paddy field ridge channel area. To maximize irrigation effects, it was imperative to strengthen management of water lateral seepage within the fields during controlled irrigation implementation. Lateral seepage in paddy fields subjected to irrigation and drainage regulation primarily occurred in the field bund soil at a depth of 10 ~ 20 cm. Water percolation channels were presented at depths of 10 ~ 20 cm below the ground surface. By implementing effective waterproofing measures at this depth, it can significantly reduce the loss of field moisture. The research revealed the lateral seepage process and its responsiveness to soil moisture changes in the paddy field bund canal transition zone under irrigation and drainage regulation. The insights gained aim to serve as a reference for the efficient utilization and meticulous management of agricultural water resources.