Cellular morphogenesis is essential for the well-being of cells. Polymer vesicles have been used as simplified models to mimic the shape transformation of cells, either to elucidate the deformation mechanism or to create novel materials. In this thesis, we focus on the programmable shape engineering of polymer vesicles. The following achievements have been demonstrated in this thesis: (i) A new method, where polymer addition is developed to induce the shape transformation of polymer vesicles by building an osmotic gradient over the vesicular membrane. (ii) A new deformation pathway, where the stretching deformation and bending deformation of polymer vesicles are coupled. (iii) A new mechanism, where the force analysis is proposed to interpret the shape transformation of polymer vesicles. (iv) A new characterization technique, where the loading of molecular probe onto PEG corona is used to measure the surface area of polymer vesicles in anisotropic shapes, which promises the study of the deformation mechanism. With these achievements, polymer vesicles have been engineered into a variety of shapes, including the sphere, ellipsoid, tube, disc, stomatocyte, nest, large compound vesicle, stomatocyte-in-stomatocyte, disc-in-disc, disc-modified tube, and tubular stomatocyte. We envision that the results of this thesis will facilitate the development of nanomaterials with well-defined shapes.