Working principle of vegetable seed metering device in pneumatic plate-type was put forward. Correlative structure was designed. Qingjiang cabbage seeds were selected for sowing performance test. Single factor test results showed that with the increase of diameter of suction hole, single-seed rate began to increase and then decreased, multi-seed rate increased, empty-seed rate began to decrease and then increased. Influence of diameter of suction hole on single-seed rate, multi-seed rate and empty-seed rate was highly significant. With the increase of relative pressure, single-seed rate first increased and then decreased, multi-seed rate first increased, then decreased and last increased, empty-seed rate first decreased and then increased. Influence of relative pressure on single-seed rate and empty-seed rate was highly significant, while on multi-seed rate was not significant. With the increase of sowing efficiency, single-seed rate first increased and then decreased, multi-seed rate first decreased and then increased, empty-seed rate increased. Influence of sowing efficiency on single-seed rate and empty-seed rate was highly significant, while on multi-seed rate was not so significant. 