Abstract: To address issues of inconsistent furrow depth and non-adjustable furrow spacing in traditional seeder trenching device under different field conditions, a multi-functional trenching device for seeder has been designed．Trenching device integrated rotary tiller blades, transmission mechanisms, and a machine cover synergistically to aerate and soften soil with different moisture levels through rotary tilling, effectively resolving problem of inconsistent trench depth．Additionally, through use of limit grooves, cross pipes, and spline locking screws, spacing between furrows could be adjusted．Field trials were conducted to verify that multi-functional seeder met requirements for different crop row spacings．Furthermore, based on plowshare design parameters calculations under shallow furrow conditions and combined with finite element analysis methods, plowshare structure, and mechanical properties were analyzed to provide a theoretical basis for seeder trenching device optimization and improvement．