Aiming to address the issue that high-speed operation induces excessive vibrations of no-till seeding units, thereby deteriorating seeding quality, a dual-regulation vibration-reduction no-till seeding unit was developed based on downforce stabilization control and furrow-depth attenuation control. By integrating multiple sensors, including an inclinometer, a pin-shaft force sensor, and an angular displacement sensor, the system enabled real-time acquisition of the profiling angle, downforce cylinder thrust, and depth-limiting wheel arm rotation. Consequently, closed-loop regulation of the downforce hydraulic cylinder pressure and the damping cylinder displacement was achieved. Stable downforce output and impact-limiting damping control effectively suppressed unit vibration, enabling active regulation of downforce and seeding depth. A coupled co-simulation model of the dual-regulation hydraulic control system was constructed by using AMESim and Simulink. Simulation results indicated that PID, fuzzy-PID, and sliding-mode control (SMC) exhibited comparable performance in regulating the downforce cylinder force. However, for damping-cylinder displacement control, SMC demonstrated clear advantages over conventional PID and fuzzy-PID control, reducing the maximum overshoot by 5.56 percentage points and 2.01 percentage points, and shortening the settling time by 1.27s and 1.45s, respectively. A dual-regulation vibration-reduction test bench for the no-till seeding unit was built, and a downforce measurement model integrating profiling angle and hydraulic pressure was established. Experimental validation of the proposed control strategy showed that under different hydraulic pressures and four-bar linkage inclination settings, the coefficient of determination reached 0.94463 with an adjusted value of 0.93819, demonstrating high control accuracy of the seeding downforce. The findings can provide a theoretical foundation for vibration-reduction control of no-till seeding units.