There is disclosed a process for purification of a styrene polymer, for purifying a styrene polymer having a high degree of syndiotacticity obtained by using a catalyst comprising (A) aluminoxane and (B) a transition metal compound containing no halogen, deashing the above styrene polymer with an alcoholic alkaline solution and then washing with an alcohol. Also disclosed is a process for purification of a styrene polymer which comprises deashing the above styrene polymer having been produced with a conversion rate of 60% or more after swelling it by adding an aromatic solvent and/or a styrene monomer.According to the process of the present invention, a high purity styrene polymer can be obtained with good efficiency.