The application relates to the field of wall decoration materials, in particular to a novel high-strength gypsum thermal insulation putty and a preparation method thereof. A new type of high-strength gypsum thermal insulation putty, which includes the following preparation raw materials in parts by weight: 50-70 parts of α-high-strength gypsum, 7-10 parts of vitrified microbeads, 0.1-0.3 parts of cellulose ether, and 1 part of redispersible latex powder -2 parts, 0.1-0.5 parts of retarder, 0.1-0.5 parts of thixotropic agent, 0.01-0.05 parts of air-entraining agent; the particle size of the vitrified microbeads is 180-200 mesh; the cellulose ether includes 2wt %, Modified cellulose ether with a viscosity of 18000-22000mPa.s at 20°C. The new high-strength gypsum thermal insulation putty provided by this application can be used as gypsum thermal insulation mortar, and can also be used as gypsum putty for leveling. After construction, no additional gypsum putty is required for leveling. The thickness of one construction can reach 30mm, which reduces the construction process and smooth construction. Uniform, fine batch scraping, no color difference, excellent decorative effect, and no loss of thermal insulation performance in the later stage, no hollowing and cracking.