A mechanical model of point-collision is given for explaining the formation of ultra-high pressure in Dabie orogenic belt, central China. During the collision of the continents deviatoric stresses and average pressure in visco fluid are studied respectively. The contribution of the tectonic pressure to ultra-high pressure and its implication to exhumation of the UHP rocks are also discussed. The results show that tectonic pressure due to crustal movements may be equal in magnitude order to lithostatic pressure. The collision of the irregular boundary between two continents will produce local stress concentration. Rheological analysis of rock material have proved that in the crust the effect of increasing pressure is not very noticeable during the tectonic movements,
but in upper mantle it may be noticeable owing to the lower viscosity. So it is possible that metamorphism of UHP can be occurred in lower viscose rocks between the lower crust and upper mantle.