The mini-frac analytical technique is a means of obtaining the reservoir physical parameters and the analysis on fracturing fluid properties before the hydraulic fracturing construction and is also the technical assurance of smooth fracturing construction. This paper introduces the application process and theoretical basis of the test fracturing from the field construction work and briefly introduces several mathematical methods to find the formation closure pressure. Closure pressure is one of the key parameters of fracturing construction, which are not the same for being derived from different mathematical methods; the reliable values should be selected according to the actual test results. The pressure drop curve fitting is a method to reversely calculate the key formation parameters in the model. After fitting, the fracturing model for the construction stratum is obtained. On this basis, the main fracturing design and the fracture prediction are relatively accurate, the construction is also safe.