Abstract: In order to determine the applicability of the cavity building with large size pipe string under special geological conditions in China, taking the multi interbedded formation of a salt mine in our country as a cavity building target, many geological solutions are designed for carven building in multi interbedded formation in a salt mine. Their feasibility on site is analyzed. Moreover, the cavity rate and power consumption are contrastively analyzed, and the engineering costs of drilling, carven building, gas injection and brine discharge in single well are calculated. The results show that, to build a single salt cavern with effective volume of 38×10⁴ m³ under certain geological conditions, the large size pipe string can reduce construction period about 30%, energy consumption about 58% and cavity building investment of single well about 17%, in contrast to the regular size pipe string. Therefore, the large size pipe string has obvious advantages in accelerating cavity building progress, cost savings and reducing energy consumption. It is worthy of further research and application.