When the chip and the structure of dewar are determined,the research of the self-adjusting J-T cooler is the most important work for the quick-start IR FPA.The influence of the heat exchange tube,the pressure and the flow on the J-T cooler starting time is studied.The effect of back flow drag and self-adjusting mechanism force on the working process are described.The understanding on working process is deepened by analyzing the experimental results.The study is helpful for the development of quick-start J-T cooler.