The invention discloses an infrared light reflection heat insulation COC plastic and a preparation method and application thereof. The COC plastic is prepared from the following raw materials in percentage by weight: 50 to 99.5 percent of COC, 0.5 to 50 percent of infrared reflecting agent, 0 to 1 percent of antioxidant, 0 to 1 percent of UV (Ultraviolet) stabilizer and 0 to 10 percent of titanium dioxide. The infrared reflecting agent comprises at least one of pigment blue 28, pigment blue 36, pigment green 50, pigment green 60, pigment yellow 53, pigment brown 24, pigment brown 33, pigment yellow 164, pigment green 17, pigment brown 29, pigment black 30, pigment purple 16 and pigment purple 14. The preparation method comprises the following steps: uniformly mixing the raw materials according to the ratio, adding the mixture into a double-screw extruder through a main feeding port, and conducting extruding to obtain the infrared light reflection heat insulation COC plastic. When the COC plastic is applied to a packaging material, a packaged object can be prevented from deteriorating due to rapid temperature rise, and the COC plastic is particularly suitable for packaging temperature-sensitive components, raw materials and other products.