The invention relates to a farmland mulch holing and seedling placing device which comprises a handholding rod and an inner shell fixedly arranged at the bottom of the handholding rod. The inner shellis of a cylindrical structure, an outer shell of a cylindrical structure is arranged outside the inner shell and driven by external force to freely rotate, and a plurality of blades for cutting mulchare uniformly distributed at the bottom of the outer shell; a driving device is fixedly arranged on the handholding rod, connected with the outer shell through a transmission part and used for driving the outer shell to rotate so as to enable the blades to cut the mulch; a triggering mechanism is arranged in the inner shell, the bottom end of a triggering part of the triggering mechanism is lowerthan that of each blade, the triggering part contracts to the inside of the inner shell when receiving pressure to trigger the driving device to drive the outer shell to rotate, and when the pressureis relieved, the triggering part automatically resets to enable the driving device to stop action.