Abstract: Use of gray system theory in evaluation of thermal and moisture comfort of bast fiber fabric is introduced.The thermal transmittance,air permeability,moisture vapor transmission(MVT),and hygroscopicity of bast fiber fabric with different specifications are tested,and their thermal and moisture transmitting properties are compared with those of silk fabrics through gray correlation analysis and the thermal and moisture transmitting properties of the summer bast fiber fabrics are listed in the order from good to bad,thus providing a theoretical basis for investigation of thermal and moisture comfort of fabric.The experimental results show that the influence of fabric thickness and tightness on MVT varies with humidity.In low humidity,fabric tightness is more important than thickness,and vice versa in high humididy.