Abstract: Using 0.6-scale water modelling based on Fr-We number similitude criteria, the influences of the submerged entry nozzle configuration and operating practices on the level fluctuation in the mold which caused surface defects and mold power catching, were studied. It was found that the level flunction was resulted from gas injection, impact-ing of the stream and standing wave. The level turblence raises with the incresing of the gas injection, however the casting rate, immersion depth and jet angel of SEN have a dual influenc on the level fluctuation.