The silicon nanocone structure bio-inspired from the protuberances on the cicada wing is studied for its anti-reflection and light-trapping property. The average reflectivity of the nanocone can be reduced to 1% in the spectral range of from 300 nm to 1200 nm with optimal parameters of 150 nm bottom radius and 500 nm height. The optimized nanocone structure is compared with the slab structure and nanorods structure with the same parameters. The superior anti-reflection and absorption properties are further demonstrated by reflection curve, electrical field intensity distribution, absorption per unit volume and electron generation rate distribution. The simulation result may provide guidance for the design of anti-reflection and light-trapping microstructure in silicon photovoltaic devices.