In recent years, there has been a rapid development of demand-side flexibility resources, such as flexible loads, energy storage,electric vehicles, etc. These resources can flexibly regulate the consumption and storage of electricity without affecting the quality of electricity consumption and user experience, and can better maintain the stable operation of the power grid. However, given that most of the demand-side resources have small capacity, different characteristics and are scattered at the bottom layer, their integration into an aggregated model is usually considered in practical scheduling. For this, a feasible region approximation and efficient aggregation method for demandside resources based on improved zonotope is proposed. Firstly, the feasible region of individual demand-side resources is approximated by the zonotope based on the bottom-up idea, and the general construction form of the zonotope generator is proposed to further improve the approximation accuracy, and finally the aggregation model of demand-side resources is obtained based on the Minkowski sum and the validity of the model proposed in terms of computational accuracy and speed is verified through the analysis of the calculation examples.