Carbon dioxide (CO₂) is one of the important factors affecting vegetable yield in controlled environments. This study used cucumber as an experimental material to investigate the effects of hanging different amounts of CO₂ generation bags (CGBs) on the growth of temperature-loving vegetables under facility soil cultivation. CGBs of three different densities were set up: no application (TC), eight bags/265 m² (T1), and sixteen bags/265 m² (T2). The results showed the following: (1) Hanging CGBs at different densities significantly impacted indoor CO₂ concentration. Light, temperature, and humidity also affected CO₂ concentration to a certain extent. (2) The application of CGBs improved cucumber growth, photosynthesis, and quality-related indexes, resulting in a 28.9% increased yield compared to the control group. (3) The economic benefits of CGB application in each group were analyzed, revealing the economic benefits of high-density CGB cultivation on solar greenhouse cucumber. This study explored a low-cost and effective CO₂ generation application mode.