In this paper, we report the facile fabrication of a sheet-like polymer-based micromotor through the combination of spin coating, self-assembly, and sonication techniques. By carefully adjusting the construction conditions, such as the solution concentration, spin coating speed, and the sonication time, the size of the resulting micromotor can be finely tuned. The utilization of the polymeric materials inside a micromotor brings several advantages, such as the thermal property and the encapsulation of functional materials. As a consequence, the resulting micromotors can not only undergo shape variation from sheets to spheres at an elevated temperature but also exhibit the magnetic response based on the encapsulated magnetic nanoparticles. Furthermore, by combining these two different properties, a new strategy to realize the controlled cargo capture, transport and release based on the polymer's softening property is proposed in this work. The low cost, easy processing, and versatile functions make current micromotor, an attractive candidate for practical applications, such as targeted drug delivery.