The structure and preparation method of a compound D-L2(-B)-L1-A is disclosed, A is a physiologically and pharmacologically active molecule that physically binds to a specific biological molecule or receptor; L1 is a variable structure with the molecular connection activity at both ends connecting to A and L2; L2 is a variable structure, which has three-terminal molecular connection activity connecting to L1, D and B; B is a physiologically and pharmacologically active molecule that binds to albumin, changing the A molecule in the body cyclic characteristics; D is a polycarboxylic macrocyclic structure that binds to radioisotopes; D-L2(-B)-L1-A compound can be used to express chemokine receptor 4 (CXCR4) receptors on cells, tissues, and/or organs, and after binding with radionuclides, it is suitable for detection of CXCR4 protein binding in vitro, detection of CXCR4 cell binding in vitro or detection of CXCR4 expression in in vivo animal imaging.