Scheduling nurses repeatedly is an essential work in hospitals.Good nurse scheduling has impacts on the quality of health care,the cost,the mental and physical health of nurses,and the enthusiasm of nurses for their jobs.To solve the nurse scheduling problem with a set of labor agreement rules and different grades for nurses,which is known to be NPhard,an integer linear programming (ILP) model is established.The ILP model is then extended to represent the following additional requirements:request for leave,preference to shifts and relationships between nurses.Based on the ILP model and its extended model,a nurse scheduling approach is built,in which a series of switch rules are applied.Experiments on a real problem instance prove the practicability of the models and the feasibility of the approach,and show that the extended model is more popular and helpful in increasing the work efficiency of nurses.