A multifunctional optical system for solar simulators,which could achieve collimating and divergent sunlight simulation simultaneously,was designed. The design of condensers used in the optical system,and the optimization techniques of optical integrators were described. The parameters of the optical integrator was optimized with both the sequential and non-sequential functions of Zemax software. Also the collimator objective was designed. According to the analog simulation results of the optical system with LightTools,when the collimating sunlight simulation was achieved in the designed optical system,the irradiated surface reached Φ300 mm,and the irradiation nonuniformity superior to ± 6.1%; when the divergent sunlight simulation was achieved by changing the position of collimator objective,the irradiated surface could reach Φ1 500 mm and the irradiation nonuniformity superior to ± 6.7%.