Abstract: As a pivotal technology for eliminating terrestrial network coverage gaps and enhancing global connectivity, satellite communication plays a critical role in realizing the vision of ubiquitous 6G networks. Direct-to-Satellite technology for smartphones, in particular, serves as a vital pathway to constructing an integrated space-terrestrial network and achieving the internet of everything. This technology is rapidly emerging as a focal point of research and development, garnering widespread attention. This paper analyzes multiple technical approaches and challenges associated with direct-to-satellite implementation, with a specific focus on three critical hurdles, limited frequency resources, power and weight constraints of satellite-borne antennas, and high dynamic adaptability requirements for satellite-terrestrial links, then corresponding solutions are proposed. Furthemorre, recommendations are provided to guide the future development of direct-to-satellite technology.