To solve the spectrum access decision problem in cognitive radio networks ( CＲNs) ，the spectrumaccess procedure of secondary users(SUs) can be modeled as a non-cooperative game． In view of the fact that theprimary user( PU) has higher priority to access the radio spectrum，this paper set up the system model based on theM / G /1 queueing theory with server breakdowns and analyzed the individual optimization strategy and social optimi-zation strategy separately． Based on the analysis results，this paper proposed a pricing scheme to achieve the goal that Nash equilibrium actions of SUs lead to social welfare maximization． The simulation results indicate that the price-based spectrum access strategy can improve the efficiency of spectrum resource allocation and satisfy the need of the whole society．