Objective　To explore the extent of dural de-stretching suture matched with the standard large trauma volume compensatory.　Methods　20 cases of standard large decompressive craniectomy were measured and calculated the average adult compensatory volume of the decompression of the measurement window. The skull of the cadavers were used to simulate the process of dura mater defects tension, and found the volume of defects caused by the extent of dural tension (area to express), in order to quantify the reduce tension extent of dura mater.　Results　The average compensate volume of the adult standard large decompressive craniectomy was about 81ml, and the area caused dural tension defect was about 26.5cm2, which would be effected by the age, the range of bone flap, the degree of brain atrophy, delayed cerebral edema, intracranial hematoma, cerebral infarction, scalp tension and so on.　Conclusions　For dural de-stretching suture, the optimal repairing area of dura mater is about 26.5cm2, which should be revised according to the individual compensatory volume.