Abstract: According to the technical requirements of BT110TS special collapse-resistant and anti-H₂S casing,and based on the effects by relevant chemical elements in the steel,the steel is designed as 26CrMoVNbRE.In addition,as per the Baogang-owned equipment and process for manufacturing the low alloy CrMo tubing and casing,the manufacturing process for the said special casing is designed.The trail production result demonstrates that the mechanical properties of the casing are in conformity with the applicable technical requirements for high strength and high toughness,and the collapse resistance value of the casing is 52% higher than that as specified under relevant technical requirement.Moreover the casing is also up to the 80%YS_min H₂S threshold requirement as specified under Standard NACE 0177 Method A.