The invention discloses a water-based nano reflection and heat insulation transparent coating and a preparation method thereof. The formula of the coating comprises the followings in percentages by weight: 35%-50% of a water-based acrylic emulsion, 5%-15% of water-based lithium silicate, 5%-15% of a water-based polyurethane emulsion, 5%-10% of a water-based heat insulation nano dispersion sizing agent, 5%-10% of a water-based heat insulation and heat preservation nano dispersion, 2%-12% of a wetting dispersant, 0.2%-0.5% of a flatting agent, 0.2%-1% of a thickener, 0.1%-0.2% of an antifungus and anti-mildew agent, 0.5%-2.5% of a coalescing agent, 0.5%-2% of a silane coupling agent and 5%-25% of deionized water. According to the water-based nano reflection and heat insulation transparent coating disclosed by the invention, under the precondition of without influencing lighting, heat radiation is blocked and infrared heat energy is prevented from being conducted into the interior of a base material through effective reflection and heat energy conduction, and thus the effects of heat insulation and heat preservation are reached. Heat energy, entering the room through the base material, generated by an outdoor heat source can be effectively blocked in summer, and indoor heat can be effectively blocked from being dispersed in winter, so that the application of refrigeration and heat preservation equipment can be effectively reduced, and the energy-saving effect is obvious.