Slurry leakage is one of an engineering phenomenon during cofferdam seepage grouting process. It is important to take reasonable and effective way to solve problems related to slurry leakage in cofferdam seepage grouting project. With regard to a large number of slurry leakage cases in a cofferdam seepage grouting process during the Central Yellow River Diversion Project, field engineering conditions and reasons for the slurry leakage were analyzed, and proposal on adopting cement-sodium silicate double solution grouting technology was put forward to solve the problem. On the basis of analyzing coagulation hardening mechanism of cement-sodium silicate slurry, field application of cement-sodium silicate technology was analyzed, referring to grouting material, grouting method, grouting pressure, grouting end condition and hole sealing. Pressurized water experiment of inspection hole has shown that water permeability of lost circulation formation is much lower after cement-sodium silicate grouting treatment than before. It meets the design requirements by achieving the effect of blocking slurry leakage.