Along with the expansion of oil and gas exploration, deep well, superdeep well and superhigh pressure well will be drilled more and more and the deep-lying strata must be turned into the major targets for oil and gas exploration and development. The poduction testing technology of deep well deals with many scientific disciplines, has great difficulty in techniques and faces with many outstanding problems as insufficient practical experience because of weakness in deep well testing works; lacking in the research organization and personnel being engaged in deep well test technology; lack in the research on the basic theory of deep well production testing and lacking in foreign scientific and technological information about the testing and completion techniques of the superdeep,superhigh-pressure and corrosive fluid-bearing wells, etc. The control techniques of testing technology of well Xin-851, a high-temperature, high-pressure and high-production well, are introduced in the paper, i. e. to predict accurately maximum shut-in pressure by static gas column accuracy formula so as to ensure the safety of wellhead; to acquire wellhead flowing temperatures at different production rates by combining the empirical equation of predicting wellhead temperature during testing in the USA with the actual situation in Xinchang gas field; re calculate accurately the heating quantities needful for preventing hydrates from being formed according to wellhead flowing temperatures when 3-stage depressurization is used; and to guarantee the surface flow paths unblocked by applying some reasonable heat-insulated measures so as to finish the resting works in the well smoothly and safely, thus providing valuable practical experiences for and high-temperature high-pressure gas well testing.