Payload resources of electromagnetic spectrum monitoring (ESM) satellite are relatively rare. In order to execute monitoring missions effectively, it is necessary to allocate and adjuct payload resources dynamically. This paper presents a ESM satellite mission planning model which takes into account payload resources’ dynamic adjustment and respective constraints for mission execution. Then, a two-tier hybrid scheduling approach (TH-SA) is designed. The first layer of the TH-SA method uses a genetic algorithm to deal with sequences of tasks that are not dynamically adjustable, and the second layer is based on heuristic rules for planning tasks that can be dynamically adjusted. The advantages of mission dynamic adjustment are verified through simulation experiments, and results show that the proposed algorithm can effectively improve the performance of ESM satellite mission planning.