Abstract: An improved particle tracking algorithm based on unstructured grids and hybrid grids with arbitrary polygon faces is presented.A dummy triangulation of non-planar polygon faces is carried out as tracking particles across arbitrary hybrid cell faces.Feasibility and reliability are shown through numerical examples.cpu time of the algorithm is compared with that of two algorithms introduced by Haselbacher et al for particles spray into a fixed chamber.The speed up can reach as high as 47% for 10000 particle tracking.