Abstract: Path finder of discovering the sky at the longest wavelengths (DSLP) is a pioneering mission of interferometric radio astronomy at the longest wavelengths on the lunar orbit. Operating frequency of DSLP ranges from 1 to 30 MHz, and one of its key technologies is the broadband active receiving antenna. This paper describes the scheme of DSLP active antenna, and focuses on its noise characteristics. The research results show that the active antenna is not a combination of passive antenna and preamplifier in the traditional sense, its main function is impedance matching, and it takes into account the noise requirements.