Abstract: The flexible LED filament is a new type of LED light source. Arbitrary bending and stretching filament was prepared by encapsulating multiple flip chips in series in the flexible transparent substrate, so as to realize full angle illumination of 360°. The problems of rigid LED filament such as light absorption, poor plasticity, complex structure and cumbersome manufacturing were solved, which further ensured the application and popularization of LED filament, and promoted the development of the LED filament lamp. The present research status of flexible LED filament in packaging structure, packaging materials, packaging technology, heat dissipation technology was summarized, which was of certain guiding significance for the practical research and application.