Chitosan membrane equipped in an apparatus was used to separate water vapor evaporated form moist paddy out of the apparatus. The said apparatus was called “membrane reactor” in this research. It was aimed as an alternative in drying moist paddy instead of the traditional open air technique encountering rainy or flooding problem. The prototype of membrane reactor was designed from mathematical air flow pattern analysis results. It was found that the reactor in horizontal flow mode with baffle plate and triangle air flow path (HF+BF+TFP) associated with membrane dried circulation air (TypeA membrane reactor) was the appropriate feature. The chitosan membranes studied in this research were uncrosslinked dense, crosslinked dense, uncrosslinked composite-on-spunpond and crosslinked composite-on-spunpond membranes. The hydrophilicity sequence in term of pure water vapor flux were crosslinked composite > uncrosslinked composite > crosslinked dense > uncrosslinked dense with the value of 608.7±99.4, 364.6±22.2, 205.8±13.5 and 120.6±18.4 g/m2/hr, respectively. The highest drying rate of membrane reactor equipped with uncrosslinked dense, crosslinked dense, uncrosslinked composite and crosslinked composite were occurred in the first hour of operation at 0.0464±0.0004, 0.0517±0.0067, 0.0578±0.0009 and 0.0715±0.0049 kg water/kg wet mass/hr, respectively. Comparing to the drying rate by an open air technique and a hot air oven at 40oC of 0.0527±0.0007 and 0.0402±0.0007 kg water/kg wet mass/hr, respectively, it could be stated that the chitosan membrane reactor could be used as an alternative in drying biomass such as paddy. It was found that the crosslinked composite chitosan membrane reactor could reduce the moist paddy from 22.8±0.4% to 15.7±0.9% within 1 hour.