The invention provides a water-based high-fullness clear primer. The preparation method of the water-based high-fullness clear primer comprises the following steps: firstly, sequentially putting A1 and A2 into a dispersing cylinder, putting B1, B2 and B3 into the dispersing cylinder after the A1 and the A2 are dispersed, and then uniformly stirring; secondly, sequentially adding C1, C2, C3 and C4 into another container while stirring, after intensive stirring, slowly adding the C1, C2, C3 and C4 into the dispersing cylinder in a linear way, performing dispersing till no condensed oil exists on a scrapper; thirdly, firstly adding 1/2D1, then adding 1/2D1 and D2 after the 1/2D1 is uniformly stirred at an intermediate speed, and obtaining the water-based high-fullness clear primer, wherein A1 is 70 to 75 parts of self-cross-linking acrylic resin emulsion; A2 is 5 to 10 parts of water-based polyurethane resin emulsion; B1 is 0.1 to 0.2 parts of sterilizing agent; B2 is 2 to 6 parts of water; B3 is 1 to 2 parts of propylene glycol; C1 is 3 to 5 parts of coalescing agent; C2 is 2 to 3 parts of defoaming agent; C3 is 0.2 to 0.6 parts of flatting agent; C4 is 1 to 8 parts of water, D1 is 0.4 to 0.6 parts of thickening agent; D2 is 0.6 to 4.3 parts of water.