Environmental simulation system is an effective way to study the response of agro-ecological system to global change. However, current atmospheric carbon dioxide (CO_2) enrichment simulation systems have some limitations, including excessive CO_2 gas consumption, high experimental cost, disparity between the simulated and the natural environments, space limitation, lack of replications. To address these problems, we upgraded the hardware and improved the design of the CO_2 concentration and temperature gradient chambers (CTGCs) that control CO_2 gas to release accurately and cost-effectively to improve the simulation of future elevated CO_2 concentration environment. Besides, the improved CTGCs was more spacious, which allowed the growth of more crop species simultaneously. In this system we used a set of electromagnetic valves and an individual CO_2 concentration infrared sensor to constitute a multi-passageway CO_2 concentration monitoring system for real-time monitoring of the change in CO_2 concentration. A proportional pressure reducing regulator valve was also deployed at the source of CO_2 gas emission. This effectively reduced the pressure storing in the gas pipeline when CO_2 was compressed and released from the gasholder, which resulted in accurate CO_2 gas emission. The pipeline consisted of head and peripheral branch tubes which were connected to the flux regulating valve. The equipment changed the CO_2 gas emission from longitudinal to lateral emission. The above changes form an evenly-distributed CO_2 gas released area in the improved CTGC system. The improved CTGC system achieved CO_2 concentrations of 3874.5, 44113.4, 49020.9, 53424.3 and 56728.9mumol·mol-1. The system improved effectively the response to environmental change, performed accurately real-time monitoring the change in CO_2 concentration in every treatment of the chamber, and released precisely CO_2 gas to maintain the targeted CO_2 concentration gradient in a stable and continuously manner. In summary, the improved CTGC system would be a better system for studying the responses of plants to CO_2 enrichment.