The key of the direct method of determining coalbed gas content is how to shorten the coal core exposure time in the sampling progress and reduce measuring error of gas content which comes from the calculation of losing gas content.The coting tests were carried out in No.24 drilling field of 715 floor gateway in Qinan Coal Mine by using traditional drill core barrel sampler and self-designed reversion seal coting equipment.The losing gas content was calculated by power functional method,and the gas content of two coting methods was determined,respectively.Results show that,compared with traditional drill core barrel sampling,the newly seal coting equipment can significantly shorten the coal core exposure time,the 30 min desorption gas content increases obviously,the calculation of losing gas content reduces by 56.99％,the desorption gas content in normal atmosphere increases by 113.24％,and the determining value of gas content increases by 10.06％.The new technology has much higher accuracy,and it is worthwhile to be popularized.