In this paper, we introduce a hybrid strategy containing pattern search (PS) optimization and genetic algorithm (GA) to resolve the problem of power allocation in cognitive radio networks. Considering the fluctuant interference thresholds in cognitive networks, an approach for solving the problem of coexistence between licensed users and cognitive users is proposed first. Then, based on the analyses of outage probability for cognitive users, a corresponding objective function with regard to the power allocation over Rayleigh fading channels is obtained. Due to the nonlinearity and complexity of this power optimization problem, it is uneasy to figure it out directly by using traditional methods, such as common mathematical deduction or linear programming. Inspired by the concept of intelligent algorithms, we try to employ the scheme of combining PS optimization and GA method, which are both efficient intelligent algorithms to resolve this difficulty. Furthermore, the numerical results are encouraging and show that the proposed approach is worthy of consideration in solving the problem of optimal power allocation in cognitive networks.