The invention provides a protein immunogold labeling method for a cryoelectron microscope. The protein immunogold labeling method comprises the following steps of (1) respectively pretreating a grid of the frozen electron microscope by utilizing a poly-L-lysine solution and PBS (Phosphate Buffer Solution); (2) putting the grid in a culture dish with the front surface facing upwards, dripping a sample onto the grid, standing, incubating, and eluting with PBS (Phosphate Buffer Solution); 3) adding a sealing agent into the culture dish, standing, incubating, and eluting with PBS; 4) adding a primary antibody, namely a specific antibody of the target protein, into the culture dish, standing, incubating, and eluting with PBS; 5) adding a secondary antibody, namely an immune gold antibody selected according to the species of the primary antibody, into the culture dish, standing, incubating, and eluting with PBS; and 6) taking out the grid, imaging by using a freezing electron microscope, andanalyzing image data to obtain a target protein structure. The method is advantaged in that an immunolabelled protein technology and a freezing electron microscope tomography technology are combined,so the target protein is observed in the freezing electron microscope imaging, and the structure is analyzed at the same time.