Timing Multi-millisecond Pulsars by 50 m Radio Telescope

Progress of study on millisecond pulsar time scales was introduced. Some characteristics of millisecond pulsar time scales defined by millisecond pulsar timing observations were discussed. Possible sources which may limit the long term stability of pulsar time scale were analysed. The 50 m radio telescope developed in China will be used for multi-millisecond pulsar timing observation and for study of ensemble millisecond pulsar time scales. A scheme for selection of millisecond pulsars to be monitord regularly by the telescope was given. Principle of timing data analyses in multi-millisecond pulsar observation was discussed.