Abstract: The incoherent scatter radar (ISR) is the most powerful tool on the ground to observe the ionosphere. The basic principle and latest progress of ISR is presented. The application prospect of ISR in the ionospheric observation, space object monitoring and space plasma physics research is investigated detailedly by combing some measurements. And then some new method and technology being tested and applied in the ISR are described. The work is of importance to improve the ability in the ionospheric observation and research and strengthen the scientific output and application of the first ISR in China.