Abstract: To explore the cause of carbon intensity change in the industry, this paper takes carbon intensity as the output, treated economic growth, energy consumption, energy consumption structure and technological progress as the input factors, and built trans-log production function to calculate the output elasticity, which could be regarded as the contribution of each factor to carbon intensity, based on the decomposition model of Kaya identity. Then, path analysis was used to reveal the relationship between each factor and its direct and indirect influence on carbon intensity. Results show that the optimization of energy consumption structure and technological progress inhibit the growth of carbon intensity in the industry, while the increase of energy consumption and the increase of the industrial added value stimulate the growth of carbon intensity. Because energy consumption structure and energy consumption have the significant impact on carbon intensity, it's the key to reducing carbon intensity in the industry to cut down the carbon intensity output elasticity of energy consumption structure and energy consumption. Furthermore, energy consumption, industrial added value and energy consumption structure increase carbon intensity output elasticity of energy consumption, whereas technological progress has the direct inhibiting effect. Industrial added value and energy consumption accelerate the carbon intensity output elasticity of energy consumption structure directly, but technological progress and energy consumption structure have the opposite effect. Hence, in view of the industry with a strong reliance on energy consumption, to reduce carbon intensity in the industry should rely mainly on technological progress to transform energy utilization, improve energy efficiency and optimize energy consumption structure.