The invention discloses a gas content testing device, consisting of a sample storing device, a gas volume measuring device and a computer. The sample storing device is connected with the gas volume measuring device, and the gas volume measuring device is connected with the computer; the sample storing device comprises a sealing tank and a gas outlet; the sealing tank is used for storing a sample to be tested; the gas volume measuring device comprises a gas inlet, a gas storing tank, a rubber hose, a volume flow meter, a liquid storing tank, a lifter and a hanging rope; specific liquid is stored in the gas storing tank; the gas outlet is connected into the gas inlet of the gas volume measuring device through a gas pipe; the gas storing tank is connected with the liquid storing tank through the rubber hose; the volume flow meter is mounted on the rubber hose which connects the gas storing tank and the liquid storing tank, and is used for measuring the flowing liquid volume, namely the desorbed gas volume of the sample to be tested; and tested data are transmitted to the computer through a first data transmission wire. According to the gas content testing device disclosed by the invention, the automation degree, the working efficiency and the test efficiency can be greatly improved.