The invention discloses a method for the preparation of
diacerein having a structure represented by the formula (II), comprising the steps of: feeding rhein having the structure presented by the formula (I), a catalyst and
acetic anhydride into a reaction vessel, heating up to 50 to 140 DEG C under a stirring state for reaction for 0.5-8 hours, tracing the reaction progress by means of TLC, detecting the amount of the
diacerein to measure a reaction endpoint, upon completion of the reaction, cooling the temperature of reaction solution to
room temperature, separating out
solid for filtering, and recrystallizing filter cakes with
acetic acid to obtain the
diacerein; the catalyst is
metal triflates, the amount of substances in the catalyst is 0.1%-10% of the amount of substances in rhein. The invention only needs the catalytic amount of the
metal triflates to complete
acylation reaction and the catalyst can be recycled, therefore, the invention greatly lowers the production cost, has higher yield and purity, simple post-treatment and simple production period, and is a preparation method for diacerein having favorable popularization and application prospect.