The transmissive glass grating is commonly used in compact micro spectrometers and spectroscopy systems which can simplify the structure of optical system and reduce the complexity and expense of modulation. Traditional manufacturing methods have been unable to meet the increasing demands of modern industry due to the brittle and hard characteristics of glass materials. The transmission quartz glass gratings were etched using a femtosecond laser with wavelength of 1040 nm, repetition rate of 100 kHz, and pulse width of 388 fs. And the effects of laser power P, scanning speed v, and repeated scanning layer N on the etching depths and widths of quartz glass gratings have been investigated. Furthermore, the diffraction efficiency of the etched quartz glass grating sample was measured using a helium-neon laser (wavelength: 632.8 nm). The grating diffraction pattern was recorded by a CCD, and the diffraction efficiency was calculated using the gray-scale center of gravity method. In the experiment, under the condition that laser power was 442 mW, scanning speed was 380 mm/s, and scanning times was 10, the etched grating width d was 5.67 μm and the grating period D was 8.17 μm. The testing results show that the zero-order, positive first-order and negative first-order diffraction efficiency of the quartz glass grating are 24.98%,31.80% and 31.04 %, respectively.