Abstract: The expansion mechanical properties of static crushing agent were studied in detail, the effects of water-cement ratio, mixing temperature and pore size on the expansion pressure were analyzed in detail, through the data analysis, the expansion pressure curves under the corresponding conditions were obtained. By comparing the size of the radial expansion pressure at different water/cement ratios, at the same time, taking into account the flowability of the breaker, the optimum water-cement ratio of the static breaker should be controlled between 0.2 and 0.3; static cracking agent gradually increases in expansion pressure with the increasing of pore size, and the difference between the axial and radial expansion pressure gradually decreases as the Poisson’s ratio increases after hydration consolidation of the breaker; increasing the temperature of the mixing water temperature can accelerate the hydration reaction of the breaker. Summarizing and analyzing the test results of the expansion pressure under various conditions, the hydration reaction can be divided into four stages: hydration reaction preheating, rapid reaction expansion, heat dissipation and pressure reduction, and pressure stabilization.