To objectively and accurately measure the full-field deformation of clear aligners for improved clinical effectiveness and safety, a comprehensive three-dimensional deformation measurement system based on laser electronic speckle pattern interferometry has been established. The specimen's surface is illuminated with a tri-wavelength laser, generating a color speckle pattern. A phase-shift device produces a quasi π/2 phase step for all three color channels. Multi-frame images of the color speckle pattern are captured using a 3CCD color camera. Deformation phases are extracted using a 90° step four-frame technique from the separated red, green, and blue channels. A window-deformable filter effectively denoises the phase fringe patterns, allowing six derivative components to be obtained directly from the three deformation components using a digital differential method. Results show that the system achieves a precision of no more than 2.4'' for micro-rotation and better than 10 με for strain measurements. Experimental results on clear aligners align closely with expected outcomes.