Abstract: As the well drilling depth has broken through the 10,000-meter in China, accurate measurements of downhole engineering parameters, such as annulus temperature and pressure for the whole wellbore, are significant in controlling potential downhole complexities. In this present work, a new micro-measurer is developed by integrating measurements of downhole temperature, pressure, magnetic field strength, and its own dynamic signals. The micro-measurer can flow with drilling fluid from the drillstring to the bottomhole and then float up back to the ground via the wellbore annulus. Compared with other downhole measurement tools that are fixedly connected to the drill string, its ”measure-and-move-on” approach reduces the residence time in the high-temperature and high-pressure zone at the bottomhole; moreover, both the pressure and temperature at different well depth can be measured, thereby the temperature and pressure profiles of the whole wellbore can be constructed. In addition, the bluetooth low energy (BLE) technique is applied to offer the micro-measurer with the capability of wireless information transmission; while hydrodynamic optimization of the micro-measurer is carried out to design the structure of the micro-measurer, which can promote its recovery rate from downhole. In addition, an intelligent joint for releasing micro-measurers from the wellbore annulus is also proposed, aiming to overcome the limitation imposed by the nozzle on the size of the micro-measurer. Both the indoor experiments and the field tests have verified the feasibility of the newly designed micro-measurer, which is a key step for establishing a complete downhole internet of things (IoT) system to serve the intelligent drilling in the future.