Protein-hydrogel-based free-form three-dimensional (3D) micro/nano-elements with ‘‘smart’’ stimuli-responsiveness fabricated via femtosecond laser direct writing (FsLDW) have attracted increasing efforts for their wide utilities in many fields, such as bio-micro/nano-machine , biophotonics [2, 3], etc. All processes of this protein-FsLDW are carried out in proteins’ aqueous solutions, as a result of which the approach is noncontact, maskless and biocompatible. So, we applied the promising FsLDW approach, which, in the construction of protein-based 3D optical microdevices, for example, microlenses. In order to meet the requirements of optical applications, FsLDW system and processing parameters were carefully optimized to achieve high-quality surface and 3D morphology. The photo-crosslinked protein microhydrogels showed a rapid and reversible swell-to-shrink behavior once stimulated by chemical signals, by which the protein microdevices can be dynamically tuned. Because of using protein molecules as “building blocks”, protein-based microelements were demonstrated of good biocompatibility. Based on the valuable and unique merits, protein-based optical micro/nano-elements have great potential for micro/nano-bio-optics, bionics, and novel biomedical applications, etc.