To effectively solve the southern Songliao Basin oil and gas reservoir core bit selection difficulties， low rate of penetration and unstable core recovery， the core barrel and the core lifter were compared and matched， the core bit type was selected and the case-dependent core bit was investigated through the analysis of the geological characteristics of the coring interval， the XRD element component proportion， and the formation drillability. The coring assembly and coring parameters were optimized， and the coring process for different reservoirs was improved. The selected coring tool and the new coring bit were used in multiple wells with the average core recovery more than 98.98%， and the highest mechanical drilling speed up to 6.03m/h. The application of the optimized series of coring bits and the complete key technologies has solved the technical difficulties in coring in the southern Songliao Basin reservoir， which can provide reliable reference and technical support for subsequent coring.