The present invention relates to an acrylonitrile (ASA) type thermoplastic resin composition with excellent weatherability and appearance properties, and more particularly, to an acrylate-styrene-acrylonitrile type thermoplastic resin composition comprising a) an acrylate-styrene-acrylonitrile graft copolymer; b) a butadienc-acrylonitrile methylmethacrylate graft copolymer; c) a copolymer of aromatic vinyl compound and vinylcyanide compound; and d) an alkyl acrylate copolymer, which has remarkably improved appearance properties such as scratch resistance, color (color stability) and gloss as well as excellent basic properties and weatherability.