Disclosed in the present invention is a method for inducing the fusion of a dendritic cell with a tumour cell, in the fusion process, successively adding an amount of polyethylene glycol and collagen to induce cell fusion highly efficiently, wherein polyethylene glycol can make the lipid molecules of the plasma membrane at the contact point between the two cells disperse and recombine, and then the cells fuse due to the mutual affinity between the bilayer membranes at the interface of the two cells and the surface tension between each other. The collagen can retrench the cell membrane and repair the cell membrane after fusion, thereby forming stable fusion cells highly efficiently, so it is suitable for the production of specific biological products such as tumour vaccines and monoclonal antibodies etc.