The isobaric method was used to determine the bubble point pressure of the solutions of H2SiF6 ( 1) + H2O ( mass fraction, w(1) = 0.003 to 0.006) and H2SiF6 (1) + CO(NH2)(2) ( 2) + H2O (w(1) = 0.003 to 0.006, w(2) = 0.004, 0.012, and 0.020) from 323 K to 353 K. The experimental results indicated that the relationship between bubble point pressure P-v and the temperature T can be fitted as the following equation: log(P-v/kPa) = A + B/(T/K).