The invention discloses a sodium dichlorophenolate sustained-release tablet, and a method for controlling sustained-release of sodium dichlorophenolate sustained-release tablet. The sodium dichlorophenolate sustained-release tablet comprises sodium dichlorophenolate and HPMC high polymer material, the sodium dichlorophenolate accounts for 58.6-71.6% of the sum of the granules or the powder, wherein, the viscosity range of the granules or the powder of the prepared sodium dichlorophenolate sustained-release tablet is respectively 411-471centipoise and 955-1015centipoise. The sodium dichlorophenolate sustained-release tablet has quality conforming to the standard and similar release property with the preparation of the same type sold in markets, and the quality control is carried out before production, thus reducing re-doing, saving production cost, reducing energy consumption and improving productivity.