Abstract: This paper describes the design and implementation of an interpreter of the first-order logic program named IFLP, which is based on Transputer. It highlights the implementation method of the syntax analysis phase and the unification-backtrace algorithm phase which are kernels of IFLP. In addition, an instance of executable programs is given. Our IFLP has the capability of dynamic tracing, which can record and point out the steps of logic inference and traces in solving problems, and help users to understand the dynamic behaviour of programs and to test the complex logic programs.