With the trend of digitalization, intelligence, and integration in the industrial Internet of Things, the scale and complexity of physical quantities that control systems need to perceive are rapidly increasing. Among them, digital temperature sensors can directly convert temperature information into digital signals, with various advantages such as low cost, low area, low power consumption, small area and digital output. They can monitor system temperature data in real time and cooperate with feedback mechanisms for feedback adjustment. They have been widely used. Among various digital temperature sensors, the digital temperature sensor based on CMOS parasitic transistor (BJT) technology is easier to implement in the manufacturing process, and has high stability and precision, making it the preferred choice for industrial production. This article focuses on the implementation of temperature sensing digital temperature sensors based on BJT characteristics, summarizing their improvement routes, development status, and trends from both academic research achievements and industrial products,providing reference for subsequent temperature sensor research