I like to present a topic on SQUID which is basically derived from Josephson’s junction. SQUIDs have very bright applications in science and technology. Recently numerous scientific publications were found based on its sensitivity in detecting week magnetic field, high speed switching circuits and in quantum computation. Though SQUIDs can be extremely small (in the order of 10⁹) it requires cryogenic cooler setup to maintain the low temperature.  Nevertheless hunting High T_c superconducting material is still a hot research field in solid state physics. Being in Advance stage there has been large increasing interest for fabrication and designing of SQUIDS. In this presentation I will mainly focus on introduction to Josephson junction and how useful it is in the field of science and technology.