In order to optimize the design and forecast of the three most critical technical indicators that affect the quality of underwater concrete construction： anti-washout， slump and underwater/in-air strength ratio. Based on the experimental data， the factorial design method was used to optimize calculation and modeling. In the experiment， the water-binder ratio（m_W/m_B） was from 0.35 to 0.45， and the amount of anti-washout admixture（w_AWA） was 0.20%~1.50%， the amount of superplasticizer（w_PC） was from 1.20% to 1.80%. The results show that underwater concrete has excellent properties. The best values of m_W/m_B， w_AWA and w_PC are 0.39， 0.86% and 1.47%， respectively. The theoretical prediction is that the corresponding slump of underwater concrete is 184.0 mm and the suspension content is 113.2 mg/L， the underwater/in-air strength ratio is 77.4%.