Faced with the challenges of energy crisis and environmental protection, various countries have proposed carbon neutrality target and strategies. For a considerable period, power plant with internal combustion engines will continue to dominate. At present, the low-carbon/zero carbon fuel technology has enormous potential for energy saving and emission reduction in internal combustion engines. This course provides a brief introduction to the development background, fuel physicochemical properties, and engine application examples of low-carbon/zero carbon fuel engines, including hydrogen ammonia, natural gas, methanol, and dual fuel engines.