TLR6 (Toll like receptor 6) is a kind of pattern recognition receptors and plays an important role in resisting microorganism infection. To study the function of TLR6 in the immune response of P. fucata martensii, in this study, a full length of Pm-TLR6 was obtained using rapid amplification of cDNA ends (RACE) technology from P. fucata martensii. The expression patterns of Pm-TLR6 in all tissues and its sequential expression in the hemolymph after Vibrio harveyi stimulation and nucleus insertion operation were further detected by Quantitative Real-Time PCR technology. Results showed that the total length of Pm-TLR6 cDNA was 2295 bp, including a 5' UTR of 94 bp, a 3' UTR of 89 bp and an open reading frame (ORF) of 2112 bp which encodes 703 amino acids. Multiple sequence alignment indicated that TLR6 was highly conservative among species. The protein encoded by Pm-TLR6 has a transmembrane domain, several leucine rich repeats(LRRs) and a TIR domain, conforming to the characteristics of TLRs family. qRT-PCR data revealed that Pm-TLR6 was expressed in all tested tissues, including hepatopancreas, hemocytes, gill, gonads, adductor muscle and mantle, with the highest expression in hepatopancreas (P<0.05). After Vibrio harveyi injection, the expression level of Pm-TLR6 increased at 2 h (9 fold vs. control), then dropped to normal levels at 6 h and began to increase at 16 h, with the highest level of expression appearing at 24 h (29.4 fold vs. control, p<0.05). The result of nucleus insertion surgery showed that Pm-TLR6 expression level was not significantly changed at 5 d and 10 d, and began to increase at 15 d and 20 d (P>0.05). Its expression reached the maximum level at 30 d with significant difference (5 fold vs. control, p<0.05). These results indicated that Pm-TLR6 may play an important role in the immune defense reaction of P. fucata martensii.