Due to the harsh environment, the maintenance of offshore wind turbines (OWTs) is very difficult and the failure rate is very high. Improving the condition monitoring technologies will be beneficial to promote the performance of OWTs. Motivated by the application advantages of wireless sensor networks (WSNs) in environment monitoring, a wireless network based condition health monitoring system for OWTs is proposed, which is composed of different types of wireless sensor nodes. Sensor nodes are deployed on the key components of OWTs based on the fault feature analysis on the different components. In order to guarantee the reliabilities of information collection and communication of the sensor nodes, the principles of the deployment and communication of the sensor nodes are presented and the cluster-based distributed wireless sensor network topology is adopted to increase the efficiency of the system. An example is given to illustrate the proposed method of the condition health monitoring for OWTs.