Diamond wire sawing has gradually applied as the dominant way of silicon sawing in the photovoltaic and semiconductor industry. In the design and evaluation field of diamond wire sawing machine, little research on the static stiffness are presented. But in the design field of traditional metal cutting machine tools, stiffness is an extremely important performance index. The stiffness of wire web should be mastered to improve the machining accuracy of diamond wire sawing. The special significance of this study is that stiffness of wire web is considered to be the key index of multi wire sawing performance, as a result, wire lag and wire bow due to the loss of the stiffness of wire web could be minimized. Aiming at the problem of the stiffness of wire web, the measurement method, process and evaluation standard were proposed. The influence of the stiffness of wire web on the machining process, wire bow, cutting force, machining accuracy and other factors were studied.