The gas automatic switching central air supply device is widely used in laboratories, experimental institutes, hospitals and scientific research institutes, etc. . The automatic switching central gas supply device divides a plurality of cylinders into two groups, respectively collecting the gas in each cylinder together. After decompression, pressure stabilization, through the pipeline to the various gas point supply equipment. When it works, it first uses the gas in one set of bottles, and when the gas in this set of bottles is exhausted, it will automatically switch to the state supplied by another set of bottles, giving out sound and light alarm signals, so that the person on duty to replace the empty bottles in time; when the other group of bottles of gas, and automatically switch back to the previous state. This cycle back and forth, we can achieve uninterrupted stable gas supply. The automatic switching central gas supply device has the advantages of simple structure, safety and reliability, convenient operation and easy maintenance.