Precision cultivation is a new trend in agricultural production nowadays. The current greenhouse cultivation only uses a few of sensors to represent the overall state of the greenhouse. That couldn’t get the entire environmental conditions of greenhouse and make it difficult to implement precise cultivation in greenhouse. To utilize a quadrotor equipped with sensors to collect the environmental information in greenhouse; and locating the quadrotor is the primary task. Since the Global Positioning System cannot be used in the greenhouse, an indoor-positioning system to locate the quadrotor has to be studied. Lin (2017) has developed an indoor-positioning system which is based on UWB (Ultra-Wideband) technology but has not been able to extend to whole greenhouse. In this study, the number of anchors was increased by SPI (Serial Peripheral Interface bus) technology to extend the UWB indoor-positioning system to whole greenhouse. At present, the error of the absolute distance in the indoor positioning system is about 0.08 m. In the flight test, the quadrotor could fly on the scheduled paths and collect the environmental information.