T cells play an important role in the onset and progression of systemic lupus erythematosus (SLE), and the biases in T cell receptor beta variable (TRBV) region families and complementarity determining region three (CDR3) composition in SLE patients and mouse models have been widely reported. However, the relationship between the composition and variation in the TCR β-chain CDR3 repertoire and SLE has not been established. Here, we compared and analyzed the thymic and splenic TCR β-chain CDR3 mRNA sequences by Roche 454 high-throughput sequencing from MRL/lpr mice at different ages. Our results indicate that diversity in the TCR CDR3 repertoire from the thymus and spleen from MRL/lpr mouse was significantly decreased with increased age (disease progression) and showed a bias in usage of common TRBV and TRBJ families. The N1 region insertions in the highly expressed CDR3s significantly increased with disease progression. This study provides a new perspective for studying SLE with progression of disease in clonal level of TCR, which may provide a basis for studying the mechanism of the MRL/lpr autoreactive T cells response and tailor an individualized treatment targeting these T cells.