In this paper, the internal rolling process is presented to connect the titanium tubes to the tube fitting with the mechanical method. The material flow, the distribution of stress and strain and the connecting mechanics are analyzed by using the finite element method(FEM) for two kinds of the tube fitting structures, the triangle grooves and the rectangle grooves. Rolling experiments and tests for pressure durability, gas-sealing ability, surface finish and contact percent are also introduced. Results show that the tube joints with the triangle grooves has very excellent connecting strength, and the FE analysis agrees well with the experiments.