A high-speed camera was used to investigate the flow pattern of liquid film. Four regimes were identified as: droplet flow, strand flow, discontinuous film flow and continuous film flow when liquid flow rate increased gradually. Moreover, the critical flow rate of water, ethanol, ethylene glycol and glycerin solution under different rotate speeds were tested. Then the Gaussian process was adopted to predict more data. Results indicated that the critical flow rate increased with the growth of surface tension and decreased as the viscosity increased at certain rotate rate.