We report on the formation of Bi2ZnB2O7 crystal structures with designated patterns in ZnO-Bi2O3-B2O3 glass by femtosecond laser direct writing. The crystallization mechanism in glass is investigated by crystallization kinetics analysis and simulation of the three-dimensional temperature field distribution. The crystallized regions show larger third-order optical nonlinearity than the unirradiated region in glass by Z-scan technique. This finding is of great potential in application of nonlinear optical integrated devices and development of new nonlinear materials.