A Remote Online Carbon Dioxide (CO2) Concentration Monitoring System Is Developed, Based On The Technologies Of Wireless Sensor Networks, In Allusion To The Gas Leakage Monitoring Requirement For CO2 Capture And Storage. The Remote Online CO2 Monitoring System Consists Of Monitoring Equipment, A Data Center Server, And The Clients. The Monitoring Equipment Is Composed Of A Central Processing Unit (CPU), Air Environment Sensors Array, Global Positioning System (GPS) Receiver Module, Liquid Crystal Display (LCD) Module, And General Packet Radio Service (GPRS) Wireless Transmission Module. The Sensors Array Of CO2, Temperature, Humidity, And Light Intensity Are Used To Collect Data And The GPS Receiver Module Is Adopted To Collect Location And Time Information. The CPU Automatically Stores The Collected Data In The SD Card Data Storage Module And Displays Them On The LCD Display Module In Real-time. Afterwards, The GPRS Module Continuously Wirelessly Transmits The Collected Information To The Data Center Server. The Online Monitoring WebGIS Clients Are Developed Using A PHP Programming Language, Which Runs On The Apache Web Server. MySQL Is Utilized As The Database Because Of Its Speed And Reliability, And The Stunning Crossbrowser Web Maps Are Created, Optimized, And Deployed With The OpenLayers JavaScript Web-mapping Library. Finally, An Experiment Executed In Xuzhou City, Jiangsu Province, China Is Introduced To Demonstrate The Implementation And Application