The unit-load method is often used to calculate the displacement of statically indeterminate structure in structural mechanics to find the actual displacement state and the virtual unit-load state and combine both states to solve displacement. However, the enormous workload will arise when this method is used to solve the statically indeterminate structures bearing complex loads. A new unit-load method, which was improved by the displacement reciprocal theorem, put the loads acted on the original structure to any one of its force-method primary structures, and combined this state with the virtual state whose unit-load acted on the original structure to solve displacement. Since the primary structure was statically determined, the workload would be efficiently decreased. Thus, the improved method is valuable in practical application of structural mechanics teaching and provides a new option for teachers and students as an addition of the course contents.