The aluminum tube with rectangle cross-section can be produced by non-mandrel drawing process.It is an effective method to study the deforming mechanisms by simulation,based on which the relevant die with reasonable dimensions can be designed to ensure tube precision.The dynamics model and elasto-plastic FE model of the non-mandrel drawing process were established based on FEM software deform-3D,then the simulation was performed.The influence of different semi-die angle a2 on drawing load was researched,and a proper value of a2 and a1 was found.As for the blank instability during drawing process,the stress distribution along the rectangle sides was achieved.Then the drawing die sizing section was modified to eliminate instability.Furthermore the varying of minimum distance between blank and die during drawing process was analyzed for getting the touch boundary and touch-stress distribution.