Serious regional pollution of air, water and soil has become the focus of the whole society. Low carbon transition as well as sustainable development is the key task for textile industry since it is one of industry with high energy consumption, GHG emissions and pollution. The calculation of the carbon footprint for textile products will be very helpful to change current status. However, it is still an international problem to calculate the industry carbon footprint (ICF) of the textile and apparel quickly and accurately. On the basis of modular theory, this paper aim to solve above-mentioned problems. In this paper, the complicated product manufacturing stage was decomposed into industrial carbon footprint unit (ICFU) with definite relationship as well as clear boundary. The modular decomposition methodology, the allocation method, the parametric model were set up. And the modular calculation methodology for ICF of textile and apparel products was established accordingly. A case study based on cotton jeans manufacturing and seven fabrics knitting was performed to demonstrate that the method contributes to the accurate calculation of carbon footprint of different types of CFU, which will help the industry and companies take specific and effective measures for emission reduction and sustainable development.