Gas-based microfluidic devices and operating methods of gas-based microfluidic devices are provided. The gas-based microfluidic devices comprise a drive module and a microfluidic platform, in which the microfluidic platform further comprises a microfluidic element having an injection chamber, a process chamber, an air chamber, an overflow channel, a barrier, and at least one detection chamber. Gases in the air chamber enable solutions to move toward the direction opposite to the centrifugal force applied by the drive module. Accordingly, the operating methods utilize the gases compressed in the air chamber to move solutions to difference components in the microfluidic element.