The invention discloses a preparation method of a controlled release tablet of sasanqua saponin, which comprises the steps as follows: a. the sasanqua saponin, hydroxypropyl methyl cellulose, sodium alginate and chitosan are evenly mixed; b. an ethanol solution is added into the mixed powder prepared in the step a for moistening to prepare a damp mass; c. the damp mass prepared in the step b is dried for 0.5h to 5h under 40 DEG C to 60 DEG C and then cooled to room temperature; d. fine powder in the dry matter prepared in the step c is sieved first with a sifter of 60 meshes to 65 meshes, then with the sifter of 18 meshes to 22 meshes, and then granulation is carried out; and e. finally, tabletting is carried out to obtain the controlled release tablets of the sasanqua saponin. The release speed of the controlled release tablets of the sasanqua saponin prepared by the method of the invention is respectively 20 percent to 40 percent when in water for 3h, 45 percent to 75 percent when in water for 6h, and more than 75 percent when in water for 12h. The in vitro release curve of the controlled release tablets of the sasanqua saponin prepared by the method conforms to zero-order equation.