Abstract: Abstract: There were very few studies on the propagation characteristics of wireless sensor networks in an orchid greenhouse. For deploying a wireless sensor networks system and studying the channel characteristics under orchid greenhouse, the relationship between radio frequency signal propagation characteristics and radio signals influencing factors was studied with a 433MHz carrier frequency for configuring wireless sensor networks in an orchid greenhouse. At first, the curves of the received signal strength had less fluctuation in a playground than in a greenhouse. From the contrast experiment in both greenhouse and playground, the results showed that the orchid greenhouse had a great impact on the received signal strength of wireless sensor networks. During the experiments the transmitting power, packet length, communication distance, and the location of the source of the transmitting signal had changed for obtaining the received signal strength and the packet loss rate. The experiments demonstrated that the relationship of the received signal strength and communication distance caused attenuation to exist according to a logarithmic model, and the regression coefficient R2 was in the range of 0.9246 and 0.8753. When the transmitting power was 0 dBm or -5 dBm, the wireless signal communication success rate got higher. When the transmitting power was 0 dBm or -20 dBm, the received signal strength index (RSSI) would gain more fluctuations. Furthermore, when the data transmission rate was 1.2 kbps, the packet length had little effect on the packet loss rate. The regression analysis results demonstrated the regression parameters A and the transmitting power were quadratic relationship, and it was a quadratic regression equation between the environmental factor n and transmitting power. The curved surface and filled contour of RSSI were built by analyzing the data. The wireless signal propagation characteristics of the orchid greenhouse environment were intuitively and comprehensively reflected. Besides, a model was built for calculating the received signal strength of 433 MHz in an orchid greenhouse. The simplified math model was developed for the need of engineering. Meantime, the math model could be used for predicting the received signal strength at different transmitting powers and different communication distances by the verification experiment. Finally, this research could provide specific and detailed reference for a configured WSN system in orchid greenhouses.