Based on ultrasonic vibration added in radial direction of saw-cutting ultra-thin abrasive cutting wheel, two kind of optical glasses with different physical properties were fabricated to explore the influence of radial ultrasonic vibration on saw-cutting process. The sawing force and sawing energy were deduced theoretically, and the cutting paths of single abrasive in conventional and ultrasonic assisted sawings were represented. Then K9 glass and quartz glass were machined by ultrasonic assisted sawing, during the process the effects of ultrasonic vibration on sawing force and sawing energy were tested. Experimental results show that, compared with common sawing method, apart from influence of processing parameters, ultrasonic vibration can reduce the sawing forces in the processes of K9 and quartz by 30%—50% and 50%—65% respectively, and the specific energies accordingly by 30%—45% and 50%—60%. Radial ultrasonic vibration-assisted sawing breaks the material slightly and reduces the sawing force and sawing energy, therefore can promote sawing efficiency of optical glass materials and improve processing quality.