This paper presents the analysis of an orthogonal multi-beam Lloyd's mirror interferometer for fabrication of two-axis gratings, which is employed as a measurement standard. Conventionally, for the fabrication of such complicated micro patterns, ultra-precision turning with a fast tool servo or lithography process with masks has been employed. However, they require long machining or fabrication time. Meanwhile, laser interference lithography such as the Lloyd's mirror interferometer is expected as a candidate for fabrication of such periodic micro patterns. In this paper, a new optical configuration is designed based on the Lloyd's mirror interferometer. In the proposed design, differing from the one in the previous study, two mirrors and a substrate are set to be perpendicular with each other to fabricate two-axis grating patterns having both symmetric profiles and uniform depths over the wide fabrication area, which has been difficult to be achieved in the previous study. A design and fabrication of the optical configuration for the orthogonal multi-beam Lloyd's mirror interferometer, and some experimental results with the interferometer will be reported.