Electrical responses of three-dimensional braided composites under mechanical loads are important for the design of structural health monitoring in real time. Here we reported electrical properties and electrical-mechanical behaviors of three-dimensional braided composites with different braiding angles under three-point bending load, and investigated the correlation between electrical resistance and damage of the three-dimensional braided composites. We found that change of resistance reflected damage modes of the composite. In addition, we proposed an electrical-mechanical model to explain the resistance changes of three-dimensional braided composites based on the Weibull distribution function. The results of the model verify the effectiveness and rationality of the experimental results under bending load, which provides a theoretical basis for the structural health monitoring of three-dimensional braided composites through a electrical resistance change method.