Abstract: The method of characteristics (MOC) is one of the main methods for solving reactor neutron transport equation currently. A transport theory code based on the method of characteristics and an OpenMP parallel version of the method of characteristics calculation code were developed. OpenMP is a parallel programming model with shared memory architectures, using Fork-Join parallel execution mode, which is suitable for SMP shared memory multi-processor systems and multi-core processors architecture. The code was verified and validated by different benchmarks. The numerical results demonstrate that the code can give excellent accuracy for both the neutron effective multiplication factor and relative neutron flux (normalized cell power) distribution for neutron transport problem. The use of OpenMP can obtain good acceleration effect, making the calculation time significantly reduced.