Abstract: The random factors affecting release homogeneity of suction-type metering device and their probability distribution laws are discussed. Based on the mathematical model of the intervals between seeds with releasing single seed, Monte Carlo method was used to study and obtain the effect of the metering device' s structure parameters-number of suction holes, release angle, release radius and release height, on its release homogeneity. The results may be used for reference in the design of such kind of metering devices.