Water in high pressure steam could dissolves strong alkali quickly,and a strong alkali environment of high conc-entration is locally created.Under the conditions,strong alkali can react with lepidolite quickly,and the effect of efficient alkali solution is obtained.The optimum conditions for extracting lithium from lepidolite by high pressure steam were deter-mined.The results indicated that conversion rate of lepidolite was 96.9% under the optimum conditions including the steam pressure of 9 MPa,the mass ratio of lepidolite to alkali of 1∶1.2,the reaction time of 2 h and the particle size of lepidolite of 150 μm .