Natural gas is a vital part of low carbon energy by its efficiency, clean and safe feature under the world's low carbon economy. China is currently at the critical stage of transforming to low carbon economy. Natural gas as a basic energy supports the fast growth of economy. This paper uses gray model to predict the factors of natural gas demands and their developing trend, and applies partial least square regression model to study factors in consideration of their mutual linear attributes. Regression function is applied to forecast Chinas demand for natural gas from 2018 to 2027 with the result showing a stable but slow increasing trend, a little down in 2023, annual growth rate of gross demand is at 10%. Natural gas consumption proportion will be over 10% in 2025.