Experiments Were Carried Out to Investigate the Liquid Flow Distribution at High Gas/liquid Ratios in a Cold Model Monolith Bed of a 0.048 M Diameter with 62 Cells Per Cm 2. Three Types of Distributor for the Liquid Distribution Were Used to Evaluate their Distribution Performance. Local Liquid Saturation in Individual Channels Was Measured using 16 Single-Point Optical Fiber Probes Mounted Inside the Channels. the Results Indicate that 1) the Optical Fiber Probe Technique Can Measure Phase Distribution in the Monolith Bed; 2) Liquid Saturation Distribution Along the Radial Direction of the Monolith Bed is Not Uniform and the Extent of Non-Uniformity Depends on the Distributor Design and Phase Velocities; and 3) the Tube Array Distributor Provides Superior Liquid Distribution Performance over the Showerhead and Nozzle Distributors. © 2012 Chemical Industry and Engineering Society of China (CIESC) and Chemical Industry Press (CIP).