To clarify the effect of breakaway groove on the breakaway load of emergency fuse-pin for civil main landing gear, a series of FEM simulations were conducted to study the influence of structural changes of breakaway groove on the breakaway load for outer-groove, long outer-groove, inner-groove and short inner-groove emergency fuse-pin. The breakaway load and failure mode were comparison?analyzed between inner-groove and inner-groove emergency fuse-pin by experimental tests. The results reveal that the breakaway failure of fuse-pin is extended from inside to outside. The breakaway loads increase with increasing the sectional area and exhibit a linear relationship. The breakaway load variation with the sectional area(shear strength coefficient) of through-hole pin is the maximum, followed by outer-groove pin, and the inner-groove pin is the minimum. Compared with other pins, the breakaway load of inner-groove pin is easy to control and less affected by sectional area and overall size. The fracture morphology is changed from ductile fracture of outer-groove pin to brittle fracture of inner -groove pin. Accordingly, the design of inner-groove pin meets the aviation regulations requirement for civil main landing gear.