Aiming at the problem that inconsistent seed throwing points and poor uniformity of seed spacing of posture control and driving precision metering device under high-speed conditions. A method was proposed to constrain the freedom of seed motion and guide the direction of seed throwing, a type guiding seed throwing mechanism was designed. The guiding trajectory of the seeds was reasonably planned to be thrown, thereby ensuring that the seed throwing point and initial velocity were constant. The design of the structural parameters of the guiding seed throwing mechanism and dynamic analysis of the seed to be thrown were completed. The key parameters and their value ranges that affected seeding performance were determined. The optimal parameters combination was obtained by single factor and double factor experiments, and a working performance verification experiment was conducted. The results showed that when the central angle of the constrained migration arc was 35°, the seed throwing points were more concentrated. When the operating speed was 8km/h and the radius of the guiding seed throwing arc was 24.3mm, the seeding performance was at optimal level, the qualified index, multiple index, and coefficient of variation were 91.5%, 4.7%, and 13.6%, respectively. As the operating speed was increased from 8km/h to 14km/h, the decrease of variation coefficient was increased from 0.1 percentage points to 2.7 percentage points compared with that of the original seed metering device. Using the guiding seed throwing mechanism can effectively improve the high-speed seeding performance of the original seed metering device.