Abstract: For the cavern with of rockburst, water gushing and high geostress, the researches on the on-site flexural toughness properties of the wet-sprayed concrete containing silica fume (SF) and reinforced by steel fibers are carried out to investigate the effects of steel fiber content and SF on flexural toughness index and the difference from the plain concrete. The SF is added according to 10% of the cement mass, two mass contents of steel fiber (35, 40 kg/m³) are considered in this study, and large wet spraying machine is used. The concrete specimens used in the flexural toughness experiments are formed in site, which contain accelerator of 8%. It is the first time in China that the large-scale productive experiments adopt a large number of new technologies and can truly reflect the on-site adhesion and hardening properties of the wet sprayed concrete. Through the collaborative participation of 10 institutions, the experiments are successfully completed, and the effective results are achieved. It is indicated that the crack load and the ultimate load of concrete increased, the flexural toughness is improved when the SF and steel fiber are added, and the flexural toughness index increases with the increment of the steel fiber. Especially, the load-deflection curves show the peak of the secondary hardening of shotcrete with steel fiber content of 40 kg, which means the better resistance deformation capacity and increased residual strength. So the steel fiber reinforced wet-sprayed concrete containing the SF can enhance its toughness and the capability of resisting crack and improve its brittleness characteristic.