Abstract: First, the non-completeness of the intermediate state set IS（P_j） stored by memories in RETE algorithm is demonstrated in this paper, on the basis of a state analyzing method that we proposed. The limitation and the time variances in using RETE to parallel processing are analysed. Next, RETE⁺, a model of parallel selection and full state processing for OPS 5 production system is presented and the almost-completeness of the full state set FS（P_j） processed by RETE⁺ is demonstrrated. The calculated results show that the processing time of RETE⁺ is by far faster than RETE and the time variances in state processing is eliminated. Last, the main algorithm for RETE⁺ model is described.