An oil-injected screw air compressor, characterized by: a first stage compression chamber; an air buffering chamber coupled to the first stage compression chamber; a second stage compression chamber coupled to the air buffering chamber; a first oil cooling device for cooling lubricating oil for the first stage compression chamber and the air buffering chamber; a second oil cooling device for cooling lubricating oil for the second stage compression chamber and the first oil cooling device, wherein the first oil cooling device and the second oil cooling device are connected in series or parallel; a plurality sensors (132, 142, 152) respectively located at the first stage compression chamber and the second stage compression chamber; and a control unit respectively and dynamically controlling the first oil cooling device and the second oil cooling device according to preset pressure and temperature data measured by the sensors (132, 142, 152) or pressure and temperature data measured by the sensors (132, 142, 152), and temperature data and humidity data of an environment, characterized in that the first oil cooling device further comprises a first water inlet pipe, a first water outlet pipe, and a first control valve equipped in the first water inlet pipe and controlled by the control unit so as to control a temperature of the lubricating oil for the first stage compression chamber and the air buffering chamber, and the second oil cooling device further comprises a second water inlet pipe, a second water outlet pipe, and a second control valve equipped in the second water inlet pipe and controlled by the control unit so as to control a temperature of the lubricating oil for the second stage compression chamber and the first oil cooling device. a first stage compression chamber; an air buffering chamber coupled to the first stage compression chamber; a second stage compression chamber coupled to the air buffering chamber; a first oil cooling device for cooling lubricating oil for the first stage compression chamber and the air buffering chamber; a second oil cooling device for cooling lubricating oil for the second stage compression chamber and the first oil cooling device, wherein the first oil cooling device and the second oil cooling device are connected in series or parallel; a plurality sensors (132, 142, 152) respectively located at the first stage compression chamber and the second stage compression chamber; and a control unit respectively and dynamically controlling the first oil cooling device and the second oil cooling device according to preset pressure and temperature data measured by the sensors (132, 142, 152) or pressure and temperature data measured by the sensors (132, 142, 152), and temperature data and humidity data of an environment, characterized in that the first oil cooling device further comprises a first water inlet pipe, a first water outlet pipe, and a first control valve equipped in the first water inlet pipe and controlled by the control unit so as to control a temperature of the lubricating oil for the first stage compression chamber and the air buffering chamber, and the second oil cooling device further comprises a second water inlet pipe, a second water outlet pipe, and a second control valve equipped in the second water inlet pipe and controlled by the control unit so as to control a temperature of the lubricating oil for the second stage compression chamber and the first oil cooling device.