Abstract: In view of low efficiency and high cost of artificial shelling in processing of walnut， physical properties of walnut were analyzed，and influencing factors of walnut shell-cracking were investigated，the maximum shelling stress of walnut was got of 580 N.A pneumatic walnut shell breaking device was designed，that could realize high shell breaking efficiency by using double-action cylinder.Overall structure and key components of walnut shell-breaking machine were designed and verification tests were carried out.Results showed that under condition of 2 s in a single stroke of broken shell cylinder，high walnut kernel rate and one break rate could reach 91.5% and 90.7%，and the device could handle walnuts 108 kg/h.Study results could provide reference for the large-scale development of walnut shell-cracking.