Abstract: Sequence and optimal factor combination of rotation speed of seeding shaft of buckwheat seeding device，number of single-row resisting sleeve holes and speed of seed bed belt on uniformity variation coefficient of sowing amount and average number of seeds in the interval were determined.By designing orthogonal experiment and using extreme range method to analyze orthogonal experiment results，influence degree and optimal combination of various factors on coefficient of uniformity of sowing volume uniformity and average number of seeds in the interval were determined.Using range method to analyze orthogonal results of coefficient of variation，RA=51.74，RB=2.95，RC=12.03；analyzing orthogonal results of average number of grains，RA=5.71，RB=1.25，RC=3.14.The order of variation coefficient affecting uniformity of seeding rate was number of single-row holes in seed-resistance sleeve，speed of seed bed belt and rotation speed of seed shaft.The order affecting average number of particles was number of single-row holes in seed-resistance sleeve，speed of seed bed belt，and rotation speed of seed shaft.Under condition that number of single row holes in seed resistance set was 12，speed of seed bed belt was 5 km/h and rotation speed was 160 r/min，uniformity variation coefficient of sowing rate of buckwheat seeding device reached 20.89%，was the best indicator.