The Peptide Synthesis Instrument of American Peptide Technology Company all adopt the mixing mode of "fixed reactor,stirring paddle pushing the solid-phase resin to collide with the reactants";when the stirring paddle is activated,the resin is ground and squeezed,and part of the resin is deformed and broken,which reduces the coupling rate;the broken resin seeps into the gap of the sieve plate,which influences the speed of liquid discharging.