Abstract: A rotary drum-type anti-blocking mechanism was designed to solve the problem of straw blocking when no-till planter for maize was used in wheat residue or weed-covered fields. Based on the theory of boundary layer in fluid mechanics and contrast test, the appropriate shape of the drum was parabola appearance. And the reasonable velocity of rotation of the drum was calculated as simplifying the relative motion of the drum and straw into circulative streaming of cylinder with uniform flow. Field experiments showed that the rotary drum-type anti-blocking mechanism was effective in solving straw blocking and ensuring the passing ability of the no-till planter for maize. In order to avoid seeds being placed out of seedbed, a residue separating device with 30o aperture angle was designed to set between fertilizer openers and seeding openers.