The present invention relates to a nanocomposite thermoplastic resin composition with flame resistance comprising a basic resin mixture, which comprises a rubber-modified styrene-containing graft copolymer, a thermoplastic polyamide resin and a styrene-containing copolymer, a compatibilizer, a melamine based flame retardant and an organic layered silicate. The nanocomposite thermoplastic resin composition of the present invention offers superior flame resistance without comprising a halogen based flame retardant.