In order to satisfy the requirements of micro-satellite attitude determination and control system, northwestern polytechnical university and delft university of technology have jointly developed a low-cost micro wireless automatic sun sensor (μWASS). μWASS chooses a four-quadrant detector as its sensing part, uses the low-power 51 microcontroller unit Kernel with integrated ZigBee communication protocol as its processor, and utilizes two triple-junction GaAs solar panels as its energy generating part. And a super-capacitor is creatively be used as its energy storage part. In the meantime, the space environment radiation and high and low temperature variation have been considered during the system design, and the additional protective circuit has been added. The field-of-view of μWASS is 120°×120°, and the accuracy is better than 0.5° (1σ). The average power consumption of μWASS is 30 mW. Compared with the existing analog sun sensors, μWASS is a plug-and-play component. Its measurement data can be transmitted through wireless communication and does not need any special connectors or external A/D conversion circuit, which could not only reduce the installation difficulty but also improve the system reliability of the satellite. μWASS has achieved the low cost, miniaturization and wireless of sun sensor, and it can be widely used in various micro-satellites in the future.