Abstract: Because of the difference of density of mud and slurry in inner case and annu-las,that make U-tube effect occurs during cementing which was pay more attentions to cementing engineer for long time. This paper introduce a developed controller of U-tube effect and the work princeple, surface test and applications on site. This controller’s structure are simple, safty, reliable and don’t effect cementing operation. It showed that U-tube effects are decreased with controller through 4 wells application.