The invention provides a composite thermal insulating strip for building 
doors and windows and a preparation method of the composite thermal insulating strip, and relates to the field of 
thermal insulation strips. The composite thermal insulating strip comprises the following raw materials in parts by weight: 75-80 parts of nylon resin, 10-15 parts of 
epoxidized soybean oil, 5-9 parts of epoxidized 
fatty acid methyl ester, 5-9 parts of a propylene-
ethylene grafted 
copolymer, 15-20 parts of glassfiber, 15-20 parts of 
sepiolite fiber, 8-15 parts of 
basalt fiber, 7-12 parts of nanometer titania,8-12 parts of nano 
mica powder, 3-7 parts of color master batch, 3-7 parts of 
phosphate ester, 2-5 parts of sub 
phosphate ester, 1.8-2.8 parts of an 
antioxidant, 2.5-4.2 parts of a 
lubricant, and 1.2-2.5 parts of a 
silane coupling agent. Through the synergistic effect of 
raw material components, the composite 
thermal insulation strip has the advantages that the mechanical 
toughness is high, the tensile resistance and the break resistance are high, the heat 
conductivity coefficient is low, and the composite thermal insulating strip has high 
thermal insulation resistance and durability.