Most oil pumping units (OPUs) have been using manual control in the oilfield. This existing oil-pumping system, a high power-consuming process, has the incapability of OPU's structural health monitoring. In this paper, a sensor network based intelligent control is proposed for power economy and efficient oilwell health monitoring. The proposed sensor network consists of three-level sensors: (1) several types of basic sensors, such as load sensor, angular sensor, voltage sensor, current sensor and oil pressure sensor, which are the first level sensors (FLS), are used for oilwell data sensing; (2) our developed intelligent sensors (IS), which belong to the second level sensor, are designed mainly for an oilwell's data elementary processing, main fault alarm/indication, typical data storage/indication, data/status transmission up to the third level sensor (TLS), data/status transmission between IS, and command transmission down to the OPU motor; and (3) our developed software-defined (SD) control centers with an embedded database, i.e., the TLS, are designed for hundreds of oilwells data storage/management, data processing, malfunction detection, malfunction alarm/indication, stroke-adjustment command transmission down to a specific IS for power economy and the malfunction report to the maintenance staff via global system for mobile communications (GSM) short message service (SMS). Experiment results at the Chinese Petroleum's Changqing Oilfield demonstrate our proposed sensor network based system.