Alkaline phosphatase(ALP)is a widely-distributed phylogenetic phosphomonoesterase involved in the precise regulation of the animal biological metabolism.In this study,an ALP gene,LcALP,was cloned for the first time from Larimichthys crocea. Its full-length cDNA sequence is 2 345 bp,with a 1 629 bp open reading frame encoding a protein of 543 aa.qRT-PCR revealed the expression of LcALP could be detected in all adult tissues examined,with higher expression in the eye and head kidney of both sexes.Compared with the male,the expression level of LcALP gene from female was significantly higher in the gill and brain whereas much lower in the gonad and spleen.The low levels of LcALP were observed during the multiple cells,blastula,and gastrula stages.The levels increased significantly at yolk plug stage and peaked at prehatching stage,and then declined obviously at the alevin stage.After treatment with LPS,the expression level of LcALP in muscle cell line began to decrease at 6 h and was down-regulated significantly at 12 h.When large yellow croaker muscle cell lines were treated with poly I:C,the expression level of LcALP continuously increased to the peak at 24 h.Our results suggested that LcALP might play important roles as a regulator during the embryonic development and as an immune factor under stimulation of different pathogen-associated molecular patterns.