In view of the disadvantages of high temperature pressure sensor with lead packaging in harsh environment， this paper researches studies on the leadless packaging. Firstly， the leadless packaging structure is designed and the high temperature pressure sensor chip which is suitable for leadless packaging is clarified. Secondly， the processes such as high temperature low-stress hermetic packaging， low-stress adhesive for chip and leadless electrical connection are studied， and the compatible processes are realized. Finally, the leadless packaging is applied to high temperature pressure sensor chip， and the effect of the packaging is evaluated. The experimental results show that the leadless packaging’s leak rate is 10E-8 Pa·L/s and the working temperature is 300 ℃. The research presented in this paper not only will expand the application field of high temperature pressure sensor but also will improve its adaptability and reliability.