<p>In the&#xa0;field of photovoltaic diamond wire sawing, a square wire sawing process (squaring) that makes round silicon ingots into square silicon ingots is set before silicon wafer slicing. It is often accompanied by inevitable wire lag that causes drum shape error, which leads to poor flatness and thickness of the ingots after processing. An electrical discharge assisted diamond wire sawing (DWEDS) method was presented for square sawing mono-crystalline silicon. Compared to the traditional diamond wire sawing (DWS), it improves the machining efficiency by integrating two material removal methods of diamond wire sawing and discharge machining. In this paper, a single diamond wire DWEDS was used to square saw silicon ingots as it has the advantages of cutting accuracy, surface quality, and processing efficiency compared with DWS. The flatness method was introduced to evaluate the accuracy of square sawing instead of the extreme difference method. The key indexes such as wire tension and wire bow proved that the machining time was shortened by a maximum of 25.51% and a minimum of 21.82% for the four squaring surfaces, while the machining accuracy improved by a maximum of 84.04% and a minimum of 43.5%. The feasibility of square sawing silicon by using the DWEDS method instead of DWS is proved.</p>