Abstract: The microchip-tracer technique was developed to quickly test temperature and pressure over the entire borehole while drilling,so as to identify and predict downhole complicated conditions,such as kick,lost circulation,drilling string worn and so on.The prototype tracer is small in size and low in power consumption by adopting micro-system of data acquisition,power supply and management,high temperature and pressure resistant package.It can be continuously put into circulating drilling fluids for real-time measurement of temperature and pressure over the entire borehole.The size of tracer is only 20 mm in diameter,and it can detect temperature and pressure below 100 ℃ and 20 MPa in ground test.The research shows that the tracer is a very important tool to detect engineering parameters,and plot the curves for these parameters.