Aiming to address the limitations of existing maize seeding devices, which struggle to seamlessly switch sowing modes based on the germination rates of different maize varieties, a novel air-suction maize plot seeding device with a double disc combined seeding plate was designed. This device allowed rapid switching between sowing modes by adjusting the seeding plate's position. The structure and working principle of the seed-metering device were detailed, and the key structural parameters were determined through theoretical analysis. The average negative pressure values of the holes under three sowing modes were analyzed by Fluent software, the experiment showed that there was little change in negative pressure at the hole under three sowing modes. Simulations with EDEM software confirmed that the spine-groove combination disk had good disturbance performance. A comparative bench test was conducted on the seeding performance of different seeders based on the evaluation indicators of missed sowing rate, replay rate, and qualification rate. The test results showed that with the seeding plate speed setting at 22 r/min and negative pressure greater than 4 kPa, the qualified rate of sowing double disc combined device was greater than that of conventional seeder. A sowing mode switching test was conducted for the air-suction double disc combined maize plot seeding device, with the switching state of the seeding pattern as an evaluation indicator. Tests showed that when the switching time was 1 s, the optimal switching speed of the adjacent and the interval sowing mode was 15 r/min and 26 r/min. The proposed air-suction double disc combined maize plot seeder can achieve non-stop switching of sowing modes, the research result can provide a reference for the design and optimization of air-suction seeders for maize plots.