Abstract: The SIgM λ light chain gene about 630bp was obtained from the total RNA of the chicken bursal B lymphocyte by RT-PCR , then the SIgM λ light chain gene was subcloned into the downstream of T7 promoter of the vector pET-28a to construct expression vector of pET SIgM λ. The recombinant plasmid was transformed into in E. coli BL21 (DE3) and induced with IPTG. SDS-PAGE and Western blotting analyses showed that the chicken SIgM λ light chain protein of 25.5 kDa were efficiently expressed and mainly existed as inclusion bodies ,with specific reactivity to anti-His antibodies. Moreover，it may be helpful to study its Immunologic and other biological functions．