In heterogeneous cognitive radio networks,spectrum access opportunities with spatial reuse may be provided by the different secondary users’ space position,respecting to the primary users’ ,and spatial reuse opportunities is limited by interference tolerance. To measure interference and evaluate the spatial re-use opportunity,the interference graph of user’ s space position is introduced in this paper. An optimization problem of maximizing system throughput based on spatial reuse is investigated, which is solved by the Game Theory and an optimal channel selection set is derived. The main work of this paper is to prove that this game is an exact potential game,which has at least one pure strategy Nash equilibrium and the Nash e-quilibrium point is the optimal solution of the above-mentioned optimization problem as well. Finally simu-lation results are given to verify the correctness of the theoretical analysis. Meanwhile,after considering spa-tial reuse by users' position,the system throughput is significantly increased,thus the spectrum utilization rate is effectively improved.%在异构认知网络中，认知用户相对于主用户空间位置的不同可能提供空间复用的频谱接入机会，且空间复用的机会受限于干扰容限。首先引入用户空间位置干扰图，度量干扰和评估空间复用机会，在此基础上讨论了基于空间复用的系统吞吐量优化问题，并借助博弈论求解一组最优信道选择集合，主要工作是证明了该博弈问题是至少具有一个纯策略纳什均衡的精确势能博弈，且纳什均衡点是上述优化问题的最优解。最后，数值仿真验证了理论分析的正确性，同时证明考虑认知用户位置带来的空间复用后，系统吞吐量显著增加，有效提高了频谱利用率。
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