The invention discloses an oil chromatographic test automatic sample injection device. A gas sample chamber is divided into a left chamber and a right chamber through a sample injection gas plug. An air inlet of a high-pressure boost cylinder is communicated with a gas source. A gas outlet of the high-pressure boost cylinder is communicated with the gas sample chamber. The gas outlet of the gas sample chamber is communicated with a chromatograph through a sample injection control solenoid valve and a chromatograph sample injection port. The cavity of the gas sample chamber communicated with the chromatograph is provided with a gas extraction opening. The gas extraction opening is communicated with a vacuum pump and is used for vacuumizing the gas sample chamber. A sample injection port connector of the chromatograph is a multi-way connector and is provided with a connection port connected to the gas source. An air feeding port is arranged on a gas path connection pipe connected to thegas outlet and close to the gas outlet. The air feeding port is provided with a seal rubber ring. The device can maximally prevent manual sample injection operation errors in the oil chromatographic test, effectively reduce errors in the oil chromatographic test, improve the accuracy of the oil chromatographic test and prevents misjudgment.