To improve the combustion process of natural gas，this paper systematically investigates the research progress on ignition optimization and flame propagation enhancement technologies for diesel and natural gas dual fuel engines. By clarifying the core scientific issues of the in-cylinder premixed natural gas combustion acceleration mechanism，the characteristics of three combustion organization modes，regulation of diesel injection，enhancement of in-cylinder flame propagation enhancement，and new combustion mode of induced flame jet are emphatically analyzed. The analysis results indicate that the main technical paths to accelerate natural gas combustion include improving ignition efficiency，enhancing flame propagation speed，maintaining stable flame propagation，and shortening flame propagation distance. The induced flame jet combustion mode represents a potential way to speed up combustion of natural gas by integrating multi-point auto-ignition of diesel with flame jets generated through a throttle ring. In this mode，the combustion flame is injected into the clearance region at high speed，the differences of the start of ignition，combustion duration，and flame propagation distance among different regions in the cylinder will be effectively reduced. To further optimize natural gas combustion performance，the throttle ring structure can undergo additional refinement. Meanwhile，clarifying the mechanism of induced flame jet combustion is essential to promote the technology' s development and practical application.