A novel method of fabricating a convex microlens array with wide scope for collecting optical information and transferring it with high efficiently and excellent capabilities of withstanding external stress and temperature is presented. By lithography and ion-exchange,a hexagonal aperture planar microlens array is fabricated on a spherical glass substrate successfully under strict control of the crucial process such as coating titanium,photolithography and ion-exchange etc. There are 2052 microlens in the substrate and each one is with a length of side and an edge-to-edge interval of 0.173 mm and 0.200 mm,respectively. Measurement and test show that the ion-exchange depth is 0.198 mm,the fill factor of the array reaches 98%,and the array has significant characteristics including perfect imaging,fine optical uniformity,ion-exchanged rotation-ellipsoidal region with three-dimensional refractive index profile,intercept and numerical aperture varying from center to edge and well conforming optical performance at same radius.