Abstract: The deterministic neutron transport method has the advantage of fast calculation speed, and is capable of giving fine field distribution of physical parameters and simulating multi-physics coupling efficiently. With the application of finite element method in neutron transport calculation, high fidelity modeling and simulation can be performed for complex geometric structures and large scale radiation shielding and criticality calculation. The discrete ordinate (S_N) algorithm is an efficient method in solving the Boltzmann neutron transport equation, and the parallelization of independent ordinate directions can be easily realized by the OpenMP scheme, but the speedup effect is limited by the number of discrete ordinate directions and the computation resources on single computer node or workstation. In order to improve the calculation speed further, the geometry domain decomposition method and the MPI parallel computing scheme can be applied to extend the parallel computing capability. The domain decomposition and communication between processes were accomplished by utilizing the parallel adaptive unstructured meshes applications infrastructure JAUMIN. And the parallelization of the formerly developed finite element S_N neutron transport code ENTER was realized by implementing the parallel S_N sweeping algorithm. After verifying this parallel code on a workstation, several large scale problems on Tianhe-Ⅱ supercomputer with 1 440 CPUs were tested at most. The largest number of elements and degree of freedom were approximately 1.43×10⁷ and 2.81×10⁹, respectively, which cost simulation time of 7.4 h. The newly developed parallel neutron transport code ENTER has the capability of efficiently simulating large scale and complex geometry problems.