The invention provides a carrier assembly carrying a gene element combination, a recipient cell library, a preparation and screening method and an application, the recipient cell library is formed byfusing cells and the carrier assembly, and the carrier assembly at least carries three gene elements, respectively a plurality of first gene elements encoding one or more idiotypic synNotch receptors,respectively; a second gene element carrying one or more gene loops; a third gene element encoding one or more idiotypic chimeric antigen receptors. Wherein, when the first genetic element encodes one idiotypic synNotch receptor, the third genetic element must encode at least three idiotypic chimeric antigen receptors, and when the third genetic element encodes one idiotypic chimeric antigen receptor, the first genetic element must encode three idiotypic synNotch receptors. The gene loop is pre-programmed, a regulatory homeopathic factor is combined with a transcription factor, upon activation of the synNotch receptor encoded by the first gene element, the chimeric antigen receptor encoded by the third gene element is controllably expressed.