Relying on the FL-8 low-speed wind tunnel of AVIC Aerodynamics Research Institute, wind tunnel test research was conducted on the control efficiency and mechanism of blowing flow control with slipstream influence around conventional and blended wing-body layout seaplanes. The test utilized a small-scale half-model and an external air bridge balance. A small-volume high-power DC motor was used to drive a propeller to simulate the influence of slipstream, and an external high-pressure air source and a multi-stage flow control module were used to precisely control the flow of the flap surface air blowing system. The test verified the reliability of the relevant experimental methods and equipment, and obtained the comprehensive impact of propeller slipstream, blown air flow control, and their coupling on the lift characteristics of seaplanes. The flow mechanism of slipstream, blown air, and their coupling effects was studied through flow visualization methods. The test results indicate that the mechanical lift enhancement effects of the two layouts are limited. The lift enhancement effect is significantly improved after the addition of flap blowing control alone. When C_μ=0.12, C_Lmax increases by a maximum of 45% compared to the mechanical lift enhancement configuration. The influence of slipstream power alone can greatly enhance the lift of the aircraft. When C_T=0.45, C_Lmax increases by a maximum of 137% compared to the mechanical lift enhancement configuration. When the slipstream influence and blowing control are coupled, C_Lmax increases by a maximum of 176% compared to the mechanical lift enhancement. The coupling effect of conventional layout lift enhancement is less than the sum of individual effects, the coupling effect of blended wing-body layout lift enhancement is greater than the sum of individual effects.