This paper discusses the theoretical modeling of laser assisted direct imprinting (LADI) which utilizes a quartz mold, pulsed laser heating, and contact pressure for direct fabricating nanostructures on a silicon substrate. Based on pulsed laser heating, liquid film squeezing, and elastodynamic theories, a unified theory has successfully developed which not only quantitatively explains the fundamental mechanism of LADI but also can be used to predict correlations between the final imprinting depth and several important parameters including laser fluence, contact pressure, and feature size. To verify this theory, a series of LADI experiments have been carried out. Experimental results, in their general trends, are in agreement with the theoretical predictions and therefore supporting the validity of the modeling. Physical implications and potential applications of this modeling will be addressed.