In this paper, the molecular dynamics method is used to simulate the c-axis compression model of two voids single crystal magnesium with different arrangement positions at 300K. Combined with the stress-strain curve, potential energy curve, radial distribution function and dislocation density curve of the three models, the compression mechanical properties and structural evolution process are analyzed. The results show that the maximum compressive stress, peak potential energy and corresponding strain can be tolerated when the single crystal is parallel to the loading direction, the second is perpendicular to the loading direction, and the smallest is 45 ° arrangement with the loading direction.The results show that the double void model with 90 ° arrangement with c axis has the fastest viods closure rate.