To optimize production technology of oxy-fuel float glass, a series of float glass with lower sulphate contents and 1%~5% carbon contents in glass batch were prepared under simulated oxy-fuel melting conditions. Infrared spectroscopy，thermal dilatometer and microscope were used to study water content and its state in glass melts, the change of coefficient of thermal expansion of glass, the glass softening temperature and transition temperature, and the number of bubbles in glass, respectively. The results show that the change of carbon content will slightly changes the water content, thermo properties of glass and the number of bubbles in glass. With the increase of carbon content, the coefficient of thermal expansion and the water content of glass generally decrease, while the number of bubbles, the softening temperature and the glass transition temperature increase. When the content of sulphate is 2%, the glass with 2% carbon content has the biggest water content and the best fining effect.