<p>Over the past decade, the cold atom sensors have transitioned gradually from laboratory-based experiments to practical field applications. The miniaturization is of great importance and needs to be achieved for this transition, especially for the vacuum system for cold atom sensors. Typically, the vacuum system is complicated and usually composed of the vacuum chamber, the optical path for the laser beam, and the magnetic field coils. The improvement of size, weight, and power (SWaP) consumption of the vacuum system has become a challenge at present. In this paper, the passive vacuum technology is proposed and overviewed to simplify the vacuum system for cold atom sensors (VSCAS). Firstly, the materials of low helium-permeability are summarized. Secondly, the key components required for the realization of the passive vacuum system (PVS) are discussed in great detail, including the getter pump and atomic source. Then, the integration of the passive vacuum system with the mentioned components is summarized, and the evaluation methods of the performance of those vacuum systems have been analyzed. Moreover, we have carried out the preliminary designs and experiments of PVS, and present some experimental results to verify its feasibility.</p>