Oxygen plasma assisted molecular beam epitaxial (MBE) growth of Pr1-xSrxMnO3 thin films has been carried out on NdGaO3(1 1 0) substrates. The growth parameters have been optimized to realize nearly 2D layer-by-layer growth. XRD results of the epi-films show that the Pr1-xSrxMnO3/NGO (1 1 0) thin films are of high crystal quality, as clear ('clean') diffraction peaks can be observed belonging to the film and the substrate, respectively. Based on analysis of the peaks, it was concluded that epitaxial relation is PrSrMnO3 (1 1 0)//NdGaO3 (1 1 0), i.e., the c-axis being parallel to the surface. It is a different epitaxial relation from that of other growth methods.