Abstract: Moho depth distribution and crustal deformation pattern between different sub-blocks in Sichuan-Yunnan region are presented here based on the studies of the gravity field characteristics．Generally，Moho depth within study area decreases gradually from northwest to southeast．There is an obvious extensive crustal thickening in whole Sichuan—Yunnan rhombic block．According to the gravity characteristics，the Lijiang—Xiaojinhe fault is shown to be the southwestward extension of the Longmenshan fault；to the east of these faults，the gravity field and main structural orientation of the Middle Yunnan sub-block are consistent with those of the Yangtze block, indicating these faults and the Red River fault zone are the west boundary of Yangtze block．The 1st vertical derivative of Bouguer gravity data in Siehuan—Yunnan region is generally similar to the present-day crustal deformation pattern．The main structural orientation is NNW or nearly SN，representing the major structural orietation of a later tectonism; while it changes into nearly EW based on gravity horizontal direction derivative data after upward 45km