A novel piezoelectric actuated rail-type mobile platform is proposed in this paper, which has potential application in the inspection and maintenance tasks of the Tokamak vacuum vessel as it holds good environmental adaptability to extreme environments such as strong magnetic fields, high vacuum, and high temperature. The rail-type piezoelectric actuated mobile platform consists of a rail and a framed piezoelectric actuator operating with two orthogonal bending vibrations. The framed piezoelectric actuator moves on the rail by friction. At first, a semi-analytical model is created for the framed piezoelectric actuator utilizing the transfer matrix method, in order to reveal its dynamic behaviour. Then the prototype of the proposed framed piezoelectric actuator is manufactured and assembled, and its vibration characteristics are measured to verify the feasibility of the developed transfer matrix model. Additionally, the mechanical output performances of the rail-type mobile platform prototype are investigated experimentally, and it is observed that 1) the maximum speed of the mobile platform prototype reached 384.68 mm/s when the amplitude of the driving voltage is 400 Vpp; 2) its maximum load-weight to self-weight ratio reached 7.6 when the excitation voltage is 300 Vpp; 3) its maximum output force is almost 1.8 N under the excitation voltage of 400 Vpp; and 4) the minimum displacement resolution is 4 m when operated in the stepping mode. Finally, the extreme environment (temperature: 0~120, vacuum: 310-3 Pa~105 Pa) tests are carried out to measure the output performances of the mobile platform prototype. The results show that the platform prototype is capable of carrying loads in a high-temperature and high-vacuum environment.