The present invention discloses a thermosensitive nanocapsule and a preparing method thereof. The thermosensitive nanocapsule includes core materials and wall materials. The preparing method includes : first, making water phase and oil phase respectively, forming microemulsion by means of high speed shearing after mixing, and forming nanoemulsion via ultrasonic treatment or high pressure homogenization; then adding nitrogen to the emulsion and carrying out the reaction under a temperature of 40-80?C. for 3-4 hrs in the nitrogen atmosphere; finally obtaining the thermosensitive nanocapsule with an embedding rate of 90-94%, a particle size of less than 150 nm and a dimension polydispersity index of 0.09-0.17. In present invention, the monomer that forms the wall material of the nanocapsules is made from common biological materials, and has a good biocompatibility. The wall material has a temperature sensitivity, and can control the delayed release of core material by adjusting temperature.