The purpose of this work is to preliminarily investigate the surface structure of poly(methacrylate)/poly(styrene-co-acrylonitrile)(SAN) blend thin films cast from tetrahydrofuran solution by contact angle measurements. The main questions investigated in this work are: (1) relation between the composition of the surface and the bulk, (2) the extent of surface enrichment of the lower surface free energy component, (3) the change of the surface composition corresponding to the change in the degree of mixing in the bulk, and (4) the effect of alkyl group on the surface structure.