Abstract: Molasse is a sedimentary assemblage which is characteristic of clastic sediments and rapid accumulation on the front of mountain mass. There are three types according to their dynamic backgrounds. divergence(stretching) type, related to the crustal cracking, 2.convergence (compressional) type, related to the collision of lithospheric plates; 3. transformational shearing) type, related to stretch-rifting basin controlled by strike-slip faults. The three types of molasse are genetically related to the models of Welson moun-tain building cycles, on the account of: 1.different types of molasse formed in different stages of Welson cycles; 2.each type of molasse has its own peculiarities, due to the differences in dynamics and kinematics of platesj 3.different mineral products formed in different molasses because of the displacement and enrichment of the elements in the crust.