Abstract: In this study, a graphene-carbon nanotube-poly(lactic acid)/polyethylene glycol (Gr-CNT-PLA/PEG) phase change energy storage composite material was prepared using a solution-melt blending method. The effects of conductive particles and PEG on the crystallization behavior, electrical conductivity, and temperature-sensitive response of the PLA phase change energy storage composite material were investigated in detail. During the solution-melt blending process, the two-dimensional graphene and one-dimensional carbon nanotubes can physically hybridize into three-dimensional Gr-CNT hybrid particles under the influence of thermodynamic and kinetic factors, improving the dispersion of conductive particles in the composite material and reducing the percolation threshold to about 0.51wt%. Furthermore, the electrical conductivity and crystallization behavior of the Gr-CNT-PLA/PEG composite material are further improved by the interaction between PEG phase change energy storage material and conductive particles, and the crystallization temperature is increased from 100℃ (PLA) to about 130℃ ((Gr-CNT₅₀)_0.6-PLA/PEG₁₀). In the constant temperature-resistance test, the conductivity of the Gr-CNT-PLA/PEG composite material decreases and then increases with the increase of isothermal heat treatment temperature. In the cyclic temperature-resistance test, the Gr-CNT-PLA composite material exhibites low-temperature PTC and high-temperature NTC effects in the cyclic temperature range of 37℃ to 140℃. Through the synergistic regulation of phase change energy storage material PEG and cyclic temperature value, the Gr-CNT-PLA/PEG composite material exhibites a good phase transition energy storage platform during cooling, successfully achieving a monotonic PTC effect and high-temperature sensitivity, with a sensitivity (ΔR/R₀) up to 3000%. Moreover, with the increase of PEG mass content, the energy storage platform of the composite material can be effectively widened, up to 16.28 min, providing a basis for the preparation of high-sensitivity temperature sensors.