The invention relates to a martensitic stainless steel for an oil casing and a production method thereof. The artensitic stainless steel comprises the following chemical components in percentage by weight: at most 0.04% of C, 0.20-1% of Si, 0.30-1% of Mn, at most 0.02% of P, at most 0.010% of S, 14-17% of Cr, less than 5% and at most 7% of Ni, 1.5-2.3% of Mo, 0-0.16% of N, 0.05-2.5% of Cu, one or more of 0.01-0.10% of Nb, 0.01-0.10% of V and 0.01-0.10% of Ti, and the balance of iron and inevitable trace impurity elements. The manufacturing method of the steel comprises the following steps: heating the oil casing to 950-1100 DEG C, cooling to below 200 DEG C by air cooling, oil cooling or water cooling, and heating to 550-650 DEG C to implement tempering. The steel has a microstructure which uses a tempered martensite phase as a base phase, and contains high-temperature ferrite (delta-ferrite), austenite and other second phases of which the volume contents are respectively below 10% or the total content is below 15%. The steel provided by the invention has the characteristics of high strength (the yield strength is up to Grade 110-150ksi), strong carbon dioxide/chloride ion corrosion resistance and the like, and can partially substitute double-phase stainless steel to be used in deep wells, superdeep wells and other severe well conditions.