A cost-effective design of photocatalytic reactor needs efficient contact of the polluted substance with the solid catalyst while uniformly irradiating the solid catalyst with light. In the present paper, an immobilized photocatalyst comprising TiO2 coated on Pyrex-glass-coils (abbreviated hereafter as TGC) was developed, and a flat-plate photocatalytic reactor packed with TGC was designed. The reactor has some advantages such as low pressure drop, intensification of mass transfer; relatively uniform distribution of light radiation; high ratio of illuminated catalyst surface area to volume, and is flexible enough for large-scale application. The radiation intensity distribution and the two-flux model parameters were measured, and the two-flux model was solved numerically. The experimental values were compared with the theoretical predictions. Good agreement was obtained with a maximum deviation about 10%. Finally, the two-flux model described the radiation intensity distribution and local volumetric rate of energy absorption in the flat-plate reactor packed with TGC.