Disclosed is an improved structure of an electrical connector, which includes an upper transmission conductor assembly including an upper grounding terminal assembly and an upper power terminal assembly; and a lower transmission conductor assembly including a lower grounding terminal assembly and a lower power terminal assembly, each of which defines soldering sections, extension sections, and contact sections. The soldering sections have a width between 0.35 mm and 0.45 mm and a thickness between 0.1 mm and 0.2 mm. The extension sections have a width between 0.35 mm and 0.45 mm and a thickness between 0.1 mm and 0.2 mm. The contact sections have a width between 0.285 mm and 0.295 mm and a thickness between 0.1 mm and 0.2 mm. As such, a need for supply of a large electrical current can be satisfied and noise interference can be prevented.