In this letter, we propose two power allocation strategies, named Optimal Power Allocation (OPA) and Equal Intercept Probability (EIP), for dual-hop cooperative decode-and-forward (DF) relaying networks under constraint of intercept probability (IP). Particularly, with knowledge of channel statistics of the eavesdropping links, the transmitters such as source and relays adjust their transmit power to control the value of IP by a desired level. A max–min relay selection method is applied to enhance the end-to-end outage probability (OP). We derive expressions of transmit power for the source and the selected relay. Then, Monte Carlo simulations were performed to verify analytical results.