A tunable gradual changed Slotted Photonic Crystal Waveguide (S-PCW) was demonstrated based on subwavelength particle controller for vacuum environment. Particles can be trapped in slot structure and transported along the light transmission direction. Through thermal-optic tuning the gradual changed S-PCW, particles can be transported to the desired position. The bandgap structure and transmission characteristics of the S-PCW were analyzed, as well as the optical force with the particle. The simulation results on the power consumption of the thermal control and the temperature distribution in S-PCW show that the particle transportation in a gradual changed silicon S-PCW can be achieved through thermal-tuning the refractive index of silicon material. The calculated refractive index shift is 0.012 for position control in a 18 μm-long S-PCW with 4 nm slot width shift fron input port to output port, which corresponding to a 13.7 mW heating power. The compact device footprint shows the potential of the controller for micro manipulating applications.