Design of lightweight hole of honeycombed elliptical mirror is investigated by means of finite element method.Divisional errors of different divisional element sizes are studied,and the effects of hole array and hole diameter on different performance of honeycombed elliptical mirror is analyzed.The results show that smaller divisional error is acquired with divisional element size of 6 mm;weight, inert moment and pressure displacement are significantly influenced by hole diameter; hole array and hole diameter have great effect on thermal displacement than gravity displacement; the third hexagonal hole array with hole diameter of 80 mm is selected out as optimum hole design.