a method of forming a thermoplastic article , comprises steps of a ) positioning at least one preheated first component being hollow and having at least one open end in two co - operating first mould halves ; b ) extruding a blow - mouldable thermoplastic material into the first component and closing the mould halves ; and c ) blowing the blow - moldable thermoplastic material inside the mould halves to form an article on which the first component is fixedly engaged . the method is simple in implementation , low in cost and easy in modification , and by which a thermoplastic article of varied colors , patterns , materials , and / or functional components being fixedly mounted on its outer surface could be realized .