Provided are a low temperature active matrix display device using a plastic substrate and method of fabricating the same. The low temperature active matrix display device includes: a plastic substrate; a reflection layer disposed on the plastic substrate; a buffer layer disposed on the reflection layer; a thin film transistor disposed on the buffer layer in a first region of the plastic substrate; an interlayer dielectric layer disposed on the thin film transistor; a capacitor disposed in a trench formed in a second region of the plastic substrate and having a first electrode connected to a source electrode and a drain electrode of the thin film transistor, the trench extending from the interlayer dielectric layer to the reflection layer; and a display device having one electrode connected to a second electrode of the capacitor. The above-described structure includes photoresist spacers to decrease a leakage current from the TFT, includes a reflector to protect the plastic substrate from deformation due to laser irradiation, and employs a three-dimensional capacitor to increase an aperture ratio.