It is challenging to make modular cell-embedded microstructures with complex fine patterns and high cell-viable rates and also assemble them for in-vitro biomimetic tissue reconstruction. Here, an optofluidic thin-film lithography combined with the thin-film characteristics of the polydimethylsiloxane (PDMS) was taken advantage of microfabricating photopolymerized hydrogel-based microarchitectures with fine patterns. The photopolymerized hydrogels are composed of poly (ethylene glycol) diacrylate (PEGDA) and Gelatin Methacryloyl (GelMA). Various complex fine-pattern hydrogel microstructures were demonstrated on the designed PDMS thin-film chips (PTF chips) by using a standard epi-illumination fluorescence microscope. We took advantage of air bubble and PDMS characteristics, including the UV light refraction/attenuation, the formation of the oxygen inhibition layers, and the hydrogel photocrosslinking inhibition in this technique development. The design principle of our PTF chips is based on the physical characteristics of refraction and UV light attenuation. These hydrogels are for the assembling blocks of movable modular cell-embedded microstructures. We cross-linked the magnetic hydrogel blocks with the cell-embedded hydrogel microarchitectures of high cell-viability rates. We assembled these modular cell-embedded microarchitectures by driving the magnetic hydrogel blocks cross-linked with cell-embedded hydrogel blocks. We observed the enhancement of albumin and urea secretion for the co-culture group of HepG2 cells and 3T3 cells.