The invention discloses a ternary shuttle vector pCY which has a nucleotide sequence of SEQ ID NO:17 as shown in the specification. The invention further discloses a method for establishing CLBV (Citrus Leaf Blotch Virus) infectious cloning. The method comprises the following steps: (1) extracting total RNA (Ribonucleic Acid) of an infectious CLBV plant, carrying out reverse transcription, and carrying out PCR (Polymerase Chain Reaction) amplification with pCY-CLBV1F, CLBV1R and CLBV2F and pCY-CLBV2R respectively so as to obtain specific segments CLBV1 and CLBV2 covering the whole length of aCLBV genome; (2) carrying out digestion on pCY with Stu I and Sma I; (3) carrying out TAR (Homologous Recombination) cloning, namely carrying out co-transformation on yeast YPH501 with CLBV1, CLBV2 and linearized pCY by using a lithium acetate method, and carrying out homologous recombination so as to obtain CLBV whole length cDNA (Complementary Deoxyribonucleic Acid) cloned pCY-CLBV; (4) carryingout pCY-CLBV plasmid transformation on agrobacterium, inoculating with citruses or nicotiana benthamiana, and carrying out identification, thereby completing CLBV infectious cloning.