Small diameter wire-line coring has irreplaceable advantages in shale gas geological survey wells， but also has major limitations. In regard to the application of small diameter wire-line coring technology in more than 10 shale gas investigation wells， this paper sums up the difficulties from geological condition， technical requirements， equipment， and supporting equipment， and put forward the optimization scheme from the aspects of wellbore structures， equipment configuration， coring technology， mud system and incident prevention. With the optimized drilling measures， good results have been achieved in the following shale gas investigation wells with the core recovery rate above 97%， the rig-month footage exceeding 400m， and the incident frequency below 2 times. It can be used as reference for drilling of future small-diameter shale gas investigation wells.