Abstract: The head kidney and the spleen in Xingguo Red Carp were being compared between the fish injected with PHA and the normal group. It shows that histology of spleen and head kidney are similar to the no injection group. The head kidney is lymphoid organ which is composed of many sinusoids, blood vessels and lymphous sinusoids. The tegument surround the head kidney. The spleen is substantial organ which penetrate by the tissue of pancreas. The lymphocytes concentrate in group in spleen. The number of lymphocytes, macrophages and hamocytoblasts increase evidently in both head kidney and spleen of the fish injected with PHA. On the contrary, the number of granulocyte do not increase.