Trade openness and carbon leakage have an important impact on China's emission reduction targets. By building a panel model, this paper empirically analyses the impact of trade openness on carbon emission intensity and total emissions of all industries in the industrial sector, and verifies the existence of carbon leakage. Based on the industry characteristics and structural differences, the input-output model is deduced to measure the direct carbon emission intensity and intensity of carbon emissions embodied in net export, which are used to classify the high-carbon and low-carbon industries as the standard for empirical tests and comparative analysis. The results show that there is no positive carbon leakage in industries of low net export embodied carbon emission intensity. In contrast, there is an inverted U-shaped curve between trade opening and carbon emission intensity in industries of high net export embodied carbon emission intensity and industries of low direct carbon emission, and the inflection point has appeared. The differences of empirical results confirm that there are obvious structural differences among different industries in China's industrial sector, and some industries may have negative carbon leakage effects. So China can play a beneficial role in opening up foreign trade to improve the environment, play a structural adjustment role in the direction of opening up policy, and adopt the policy of industry environmental regulation to restrain the development of high net export carbon industry.