In the present study, development of a DSMC method for axi-symmetric flows is presented. The position of each molecule is determined through two steps. Initially the molecule moves and changes its position as it is in the three-dimensional space. Then, the corresponding location in the axi-symmetric plane is searched. A linear shape function is introduced to track the movement of molecules through triangular cells. For validation, 70° blunted cone hypersonic flow, Rothe nozzzle flow, and open hollow cylinder flare flow are computed. The results are compared with existing experiments and other simulations. The effect of rarefield gas on the wake structure is presented for the blunted cone problem. The sensitivity with respect to the grid size and the number of simulated molecules on the solution accuracy is studied for the hollow cylinder flare flow problem.