The invention discloses a production method of a polymer for a drilling fluid, comprising the following steps: dissolving 2-methyl-2- acyloxy propyl sulfonate in water, then adding water in equimolar sodium hydroxide, stirring for dissolving and cooling, mixing the two mixtures and then adding a proper amount of acrylamide and acrylic acid, stirring for dissolving, heating up the mixed liquid to 35 DEG C with introducing nitrogen, then adding an initiating agent having an amount accounting for 0.05-0.08 % of the total weight of acrylamide and acrylic acid, uniformly stirring, then introducing nitrogen for a certain time, reacting for 8-10 h at a constant temperature of 35 DEG C to obtain a gel product, cutting and pelleting the gel product, and drying to obtain the polymer for the drilling fluid. The polymer produced by the invention has strong salt resistance and calcium pollution resistance, strong ability to inhibit clay hydrating and dispersing, and strong flocculation and coating capacities, can be applied in fresh water drilling fluid, salt-water drilling fluid, saturated salt-water drilling fluid, seawater drilling fluid and other drilling fluids, and has good compatibility with other treating agents to drilling fluid.