From August 25 to October 10 in 2008, four groups of inbreed offspring of Cyprinus carpio haematopteru (HL),inbreed offspring of Cyprinus carpio var. jian (JL),offspring of Cyprinus carpio haematopteru ♀×Cyprinus carpio var. jian ♂(HJ), offspring of Cyprinus carpio haematopteru ♂ × Cyprinus carpio var. jian ♀(JH) were cultured in cages for 45 days. Then, eight serum biochemical indices and seven hematological general parameters of two hybrid and two inbreed populations were determined and compared in order to analyze the changes of hematological indices due to crossbreed and discuss the biological significance. The results show that there are significant differences on a serum biochemical index (glucose) (P<0.01) and a hematological general parameter (hemoglobin) (P<0.05) between offspring of Cyprinus carpio haematopteru ♀×Cyprinus carpio var. jian♂ and inbreed offspring of Cyprinus carpio haematopteru; there are significant differences on a serum biochemical index (total protein) (P<0.01) and a hematological general parameter (haematocrit) (P<0.05) between offspring of Cyprinus carpio haematopteru ♀×Cyprinus carpio var. jian ♂ and inbreed offspring of Cyprinus carpio var. jian. Furthermore, there are significant differences on there serum biochemical indices (total protein; glutamicoxalacetic transaminase; cholesterol) (P<0.01) and a hematological general parameter (hemoglobin) (P<0.05) between offspring of Cyprinus carpio haematopteru ♀ ×Cyprinus carpio var. jian ♂ and inbreed offspring of Cyprinus carpio haematopteru; there are significant differences on four serum biochemical indices (glutamic oxalacetic transaminase; glucose; triglyceride) (P<0.01) between offspring of Cyprinus carpio haematopteru ♀×Cyprinus carpio var. jian ♂ and inbreed offspring of Cyprinus carpio var. jian, but there is no significant difference on hematological general parameter between the two populations. The differences on hematological indices between two hybrid and two inbreed populations reflect that the level of metabolism, immunity, the function of liver, gonad development, the transport capacity of oxygen are changed in different degrees of the two hybrid populations compared with the two inbreed populations. It can be concluded that these changes are due to their different genetic compositions, because they have different parents. The correlation analysis between the hematological indices and growth behavior, stress resistance should be made in order to verify whether these changes have influence on growth behavior, and stress resistance of two hybrid populations and determine the influence degree.