The paper presents the results of a study of the plasticizing effect of oligomers based on 4.4'-dihydroxydiphenyl and 4.4'-dichlorodiphenylsulfone, as well as 4.4.-dihydroxydiphenylpropane (Diane) and 4.4'-dichlorodiphenylsulfone on polyphenylene sulfone and highly filled composites on its basis. It was established that these oligomers are quite effective plasticizers during processing, increasing the melt flow rate and retaining elastic-strength properties at concentrations up to 20%. At the same time, they have high heat resistance and the necessary compatibility with the matrix polymer.