This study concerns the efect of environment acute hypoxia on blood basic parameters of crucian carp(Carassius auratusL.)juvenile.Twelve healthy experimental fish with the body weight of (267.26±13.93)g were divided randomly into 2 groups, I,e.fish in the control group were acclimated in water with a 20℃ temperature and 7.5±0.5mg·L-1 dissolved oxygen level while fish in the acute hypoxia treatment group were acclimated in water with the same temperature but 1.0±0.2mg·L-1 dissolved oxygen level for 2 h. The venous blood pH, red blood cell counts, hemolobin concentrationswere measured and mean cell hemoglobin was estimated after 2 h experimental treatments at 20℃.The results showed that the pH of the hypoxia-treated group(5.71±0.11)was lower than that of the control group(6.21±0.07),whereaas the values of both red blood cell counts (1.05±0.6)×10 12 individual·L-1 and hemoglobin concentrations (112.0±6.7)g·L-1 in the hypoxia-treated group were higher than those of the control group,i.e.(0.52±0.04)×10 12 individual·L-1 for red blood cell counts and (70.9±8.6)g·L-1 for hemoglobin concentrations. The three blood parameters between the two experimental groups were all significantly different(p<0.05). There was no significant difference in MGH between the two groups. Acute hypoxia treatment induced higher blood re blood cell counts and hemoglobin concentrations but lower blood pH in crucian carp juvenile which might enhance the capacity of blood oxygen loading and unloading capacities.