Full-length cDNA FREP1 (fibrinogen-related protein) was cloned from larval Paralichthys olivaceus by the way of RACE PCR,and 1 131 bp length FREP1 cDNA with a 786 bp open reading frame encoded a putative protein containing a fibrinogen C terminal domain signature(WWYSRCGSAGLNG).The whole amount in situ hybridization showed that FREP1 was only expressed in intestine of 2 dph and 5 dph (days post hatching) larvae, but expressed in fin, skin, gill and intestine of 9 dph and 13 dph larvae. qRT PCR reveals that FREP1 was expressed mainly in fin, skin, gill and intestine of adult fish , but was expressed very lowly in liver, heart, kidney, spleen and muscle. If muscle expression was a control sample , compared with the other tissues the expression of FREP1 in fin and skin were highest (P<0.01). But compared with gill and intestine, the expression of FREP1 in heart, kidney, spleen, liver and muscle is much lower(P<0.05). Since it was mainly expressed in skin, gill and intestine, which was associated with innate immunity system , FREP1 may be an important member of innate immune system of P. olivaceus.