In view of the low working efficiency of silage corn harvester and the poor silking effect of corn straw，which affects the late fermentation of silage corn straw and the transformation of crude fiber，a test bed suitable for silage corn straw spinning and crushing was designed. The straw kneading broken mechanism and the roller tooth key parameters were analyzed and optimization design was conducted. It was concluded that when the two roller tooth was frontal and cooperated with the spiral of the blunt surface gap，straw extrusion，kneading and shearing effect was good，and the maize straw particles bonding model was established based on the discrete element method，using the virtual simulation of EDEM discrete element simulation software test. The impact of two roller speed ratio，number of spiral gap laps and roller speed on the rate of straw silk was explored，it was concluded that the optimal parameter combination was as follows：the number of teeth of crushing roller was 166，the speed difference ratio was 30%，the number of helical notch rings was 80，and the driving roller speed was 5000r/min. The relative error between simulation test and bench test results was 3.03%. After the bench test，Binzhou sieve was used for sieving. The results showed that the proportion of small-sized material was 38.37%，the proportion of standard material was 52.75%，and the proportion of incomplete broken material was 8.88%，which were consistent with the results of simulation test. The results showed that the screw notch sawtooth crushing roller had a higher silk rate of 8.22% than the conventional sawtooth crushing roller，which met the industry standard and achieved high crushing and high efficiency of corn stalk.