An analysis of the process of punching holes on the plastic film, grasping at the seed through suction holes, dropping off the seed and the operation mechanism of the 2BQM-2 model plastic film mulch pneumatic precision planter is carried out and a mathematical model for seed motional locus is established based on which the operation process for plastic film mulch dibbling function is simulated dynamically by use of computer simulation technology, the influence of the change of implement forward speed, seed drop off angle and the bias angle of seed receiving funnel on the seed metering accuracy is found out and the relevant parameters are optimized. The results of this research can be taken as a reference for the design of similar implements.