La2O3 doped Mo powder was pressed, sintered and cross rolled to prepare alloy plates. Then the plates were stamped to obtain molybdenum boat. The mechanical properties of the molybdenum boat were investigated under the condition of variable temperatures and loads. The influences of precipitate dispersive distribution on the mechanical properties and the influence of heating system on the stamping property were discussed for the alloy plates. And the fracture mechanism of the boat was analyzed. Results show that La2O3 of dispersive distribution increases markedly the recrystallization temperature and mechanical properties of the Mo plates. Cross rolling decreases the difference of mechanical properties between transversal and longitudinal directions, which is favorable for the stamping of Mo-La2O3 alloy plates. The maximum punch deformation can be reached when heating the 2.8 mm thick Mo-10%La2O3 alloy plate and stamping dies at 550 oC. After long-time operation of the boat in 18-tube furnace under the variable temperature and load condition, it is found that vacancy migration and dislocation slip result in dimple tear, and eventually lead to the macroscopic fracture of the molybdenum boat.