Sensor Web is a network connecting different types of sensors that are distributed around the world. These sensors can continuously monitor the environment information and generate observations. In recent years, with the advance of micro-controller and sensor technologies, the cost of constructing sensing systems has been lowered. Government agencies, scientists, and developers can deploy large-scale sensor monitoring network with a cost lower than before. However, the deployment of large-scale sensor network is still time-intensive and labor-intensive. To reduce the labor costs, automatic deployment of new sensors is the main focus of this research. However, different manufacturers produce sensors with different proprietary protocols. This heterogeneity issue causes difficulties in proposing an automatic deployment procedure. To address this issue, an ideal solution is to design a uniform way for sensors to be self-contained and to connect with web services automatically. In general, we propose a solution, Sensor Web Plug and Play, to achieve automatic deployment of sensor networks. This research first proposes a description file that can describe the sensor capabilities, and then designs an automatic registration procedure allowing sensors to automatically advertise their capabilities to a sensor web service (e.g., the Open Geospatial Consortium SensorThings API). Accordingly, the web service can create virtual identities for the sensors. Once the virtual identities are established, the sensors can continuously upload their observations to the service. To prove the concept, an agriculture monitoring application is designed and developed to monitor in-filed environmental data.