•A numerical model is developed and experimentally validated.•Fiber microstructure parameters are obtained by experimental and theoretical methods.•The heat and mass transfer performance of moisture-conducting fibers is evaluated.•The Coolmax fiber has superior heat and moisture transfer characteristics.•Ambient air parameters affect the heat and moisture transfer performance of fibers. Moisture-conductive fibers exhibit potential to serve as evaporative medium in evaporative cooling systems. Their heat and mass transfer performance significantly influences the energy efficiency of evaporative cooling systems. This study evaluated the heat and mass transfer characteristics of moisture-conducting fibers through numerical simulation based on experimental validation. The experimental systems and numerical model with moisture-conducting fibers were developed. The microstructural parameters (porosity and permeability) of fibers were determined according to experimental data and theoretical analysis. The accuracy of parameters and model was verified by experiment. The differences in heat and mass transfer performance of various types of fibers and the effects of ambient air parameters (temperature, relative humidity and flow rate) on the heat and moisture transfer characteristics of fibers were investigated through simulation. The results indicated that the Coolmax fiber had superior heat and mass transfer performance compared to Coolpass, cellulose/PET and polyester fibers. The evaporative cooling efficiency between air and fibers was facilitated by increasing air temperature, decreasing air relative humidity and reducing air flow rate under other conditions unchanged. The results are beneficial to the optimization of the evaporative cooling medium and provide theoretical guidance for the selection of fibers for evaporative cooling.