The invention relates to a genetic constitution detecting method for a cloned specific T lymphocyte TCR BV CDR3 gene, which comprises the following steps: a single nucleus cell of peripheral blood or a general RNA in tissue sample is extracted and reverse-transcribed to cDNA. The upper reach primer of the TCR BV twenty four families and a common lower reach primer BC are designed according to TCRBV gene; the cDNA is expanded using real-time fluorescent quantification PCR with dye method. The PCR product is analyzed with the melting curve; the negative primary derivative (-dF/dT) of fluorescence intensity change of the PCR product is graphed vs. the temperature (Tm); the peak graph of BV each family is obtained; the BV family PCR product showing single peak is purified and processed with serial analysis; the sequencing results are compared with the TCR Beta chain standard gene sequence. The distribution of the cloned specific T lymphocyte in tissue or peripheral blood is judged according to the appearing situation of single peak in BV each family peak graph; the genetic constitution of the cloned specific TCR BV CDR3 is determined combining the sequencing results. The genetic constitution detecting method for the cloned specific T lymphocyte TCR BV CDR3 gene has important significance in evaluating diseases related to specific cloned T cell.