To realize the rapidly tunable output of grating line selectable 9-11 μm CO2 laser, two direct-drive AC servo motors were used to drive high speed rotation and precise orientation of the grating. In the experiment, the switching time of laser lines was less than 100 μs under dual optical path mode, and the switching time of the laser line was less than 50 ms under single optical path mode. The output spectrum of laser contained 70 lines, in which the output pulse energy of 9P(20) and 9P(28) were above 100 mJ, the output pulse energy of 9R(30) and 9P(40) were above 90 mJ. The laser pulse width was shorter than 100 ns, and the repetition rate was 20 Hz.