In fields such as precision measurement and industrial testing, due to the extremely small changes in the capacitance to be measured, which may reach the order of picofarads or even lower, capacitance detection circuits are needed to capture these small capacitance changes. This article analyzes the basic principles of weak capacitance detection, distinguishing five types of capacitance detection circuits: diode type, frequency modulation type, AC type, charge discharge type, and resonant type. Through comparative analysis of measurement accuracy, power consumption, and other aspects, the characteristics, advantages, disadvantages, and applicable scenarios of each scheme are summarized, and typical application cases are listed. On the basis of summarizing current capacitance detection methods, this paper explores the limitations, directions for further research, and development trends of weak capacitance detection circuits, hoping to promote the further development of capacitance detection technology.