The invention discloses a plugging and leakage-stopping method under a flowing water condition, which comprises the following steps of: 1, arranging drill holes at a seepage water source and a water outlet of a crack or an expansion joint; 2, replacing serosity by colored water after the completion of the drill holes to carry out analog plugging; 3, testing water flow velocity, flux and water pressure parameters during the analog, and calculating and determining the relation of the water flow velocity and flux and the relation of the amount of chemical serosity and gelatinization time, so as to ensure that the serosity in the crack or the expansion joint solidifies just when the water flow flows out of the water outlet with the serosity; and 4, grouting; therefore, the plugging work under the flowing water condition is completed through the above steps. The plugging and leakage-stopping method under the flowing water condition method is suitable for plugging the concrete crack or the expansion joint seepage under the opened flowing water condition, particularly for the plugging under the opened quick-seepage or jet-flow flowing water condition, therefore, the security and the durability of the structure are improved, the service life is prolonged, and convenience in construction as well as excellent effectiveness and economic benefit can be achieved.