Abstract: A small amount of glycerol may obviouly reduce the function of PEG in the fusion of fish cells, while the presence of DMSO may greatly improve the cell fusion induced by PEG. The effect DMSO was even more prominent if the molecular weight of PEG and the concentration of PEG were relatively low. However, its concentration should not be lower than 40%, or the DMSO-dependent concentration would be ineffective. In the fusion experiment based on three groups of fish cells, we found that the number of dihomokaryons was much greater than that of diheterokaryons (P<0.05). This shows that the PEG-induced fish cell fusion has its specificity in relation to species and tissue.