Blood cells, as the main immune effector cells, play a very important role in the immune defense system of shellfish. The morphology, type and phagocytosis function of hemocytes were studied by means of blood count, Giemsa staining, transmission electron microscopy, scanning electron microscopy and fluorescence phagocytosis. The results showed that the blood cell density of the Spondylidae was 3.296×10⁶cell/mL,the blood cells differ significantly in size and whether they contain particles within the cytoplasm. Based on these differences, we made a detailed classification and subdivided them into four types: hyalinocyte cells(9.74%), granulocyte cells(58.14%), agranular haemocyte (27.50%) and lymphoid cells(4.62%). hyalinocyte cells, granulocyte cells and lymphoid cells could be observed under transmission electron microscope. Under the observation of scanning electron microscope, four different types of cells can be clearly distinguished, which are oval cells, round cells, spindle cells, nuclear (cone) cells.The phagocytosis experiment was carried out with Escherichia coli BL21 labeled with GFP fluorescent protein, and the results showed that the phagocytosis of the blood cells from Spondylidae mainly depended on granulosa cells.