This invention relates to a coal seam gas content quick desorption instrument design to test coal core, quickly and accurately determine coal seam gas content. The invention include computer processing, quick desorption and measuring system. The feature is; Quick desorption system include sample sealable tank and chip sample platform. Sealable tank top has sealing cover, and inter has whip piece. Sealable tank connect with intake pipe and vent-pipe, vent-pipe connect measuring system. Sealable tank fix on platform. Quick desorption system include measuring cylinder and water bottle, measuring cylinder's top link vent-pipe, measuring cylinder's bottom through gas tube connect with water bottle. The effect: this invention can test shattered coal core sample, pick coal seam air content data, quickly appraise this region's coal-seam gas potential stocks and exploration prospects, research differently region gas content characteristic, gas content distribution and coal reservoir bed.