Abstract: To investigate effects of dietary glutamine on activities of non-specific immune related enzymes and antihypoxia stress capacity of half-smooth tongue sole (Cynoglossus semilaevis Gnther) post larvae, four isonitrogenous and isolipidic experimental diets supplemented with 0.0%, 0.5%, 1.0% and 2.0% glutamine (with dietary free glutamine estimated to be about 0.03%, 0.46%, 0.91% and 1.73%) were formulated and fed 5 times per day to C. semilaevis post larvae (35 days after hatching, 10.640.86 mg dry weight) for 30 days before hypoxia stress test. Results revealted that the 0.5% glutamine supplemented diet significantly increased activities of lysozyme in fish whole body compared to the control group (P0.05), but different glutamine level did not impact the activities of total nitric oxide synthase and inducible nitric oxide synthase in fish whole body (P0.05). C. semilaevis HIF-1 gene were cloned and 749 bp partial cDNA sequence were obtained, which shared high identities with many other fish species. Quantitative Realtime PCR showed that glutamine supplementation did not regulate the expressions of HIF-1 in fish after hypoxia stress (P0.05). In summary, dietary glutamine could enhacne the activities of LZM and the non-specific immunity of C. semilaevis post larvae.