Abstract: Brachytherapy is one of the most important technologies in the modern tumors treatment. ¹²⁵I seed and ¹⁰³Pd seed are applied widely and maturely, ¹⁰³Pd seed is considered to be more effective in treating aggressive and fast growing tumors, and ¹²⁵I seed has obvious advantages on slower growing tumors. Seed strand and hybrid seed are two important direction of the research concerning the brachytherapy seed, especially in the ¹⁰³Pd-¹²⁵I composite seed can combine the characteristics of the two kinds of nuclides. Thus, the ¹⁰³Pd-¹²⁵I hybrid seed has important clinical significance and broad application prospect. The history of the technology is reviewed; the seeds of variety used in brachytherapy are introduced, as well as their application; the advantages and disadvantages of brachytherapy are analyzed；and the research progress of the seed is summed up.