Abstract: Total Solar Irradiance (TSI) is defined as total energy of electromagnetic radiation of all bands from the sun to any sphere (including the Earth's surface) in per unit area and per unit time. Change of TSI in solar active cycle has been considered as one of important candidate factors impacting global climate change. Monitoring and reconstruction of TSI is the important foundation for the study of the mechanism of how solar activities drive global climate change. In this article, we first reviewed the history of both ground-based and satellite- based TSI monitoring and the results they produced. Then, we analyzed the research progress on, and the problems in, using cosmogenic nuclides and celestial information to reconstruct TSI series. Finally, we provided an outlook of future directions in this field. Existing ground-based and satellite-based TSI monitoring has access to lots of TSI series of different time-scales and temporal resolution. The TSI monitoring data shows that TSI changes very little in each solar activity cycle, not enough to cause the earth surface temperature rise observed and documented in a variety of records. However, solar physics has not yet fully interpreted the physical process of TSI change, and, with limited TSI monitoring data, it is difficult to find out the mechanism of how solar activities cause TSI changes and drive the climate change. It is also impossible to accurately determine the variations of the past or future solar activities and TSI. In addition, due to instrument capacity, service time, monitoring environment and other objective factors, the TSI data has many uncertainties. Therefore, it is necessary to continue exploring the mechanism of solar activities and the TSI change, develop higher precision equipment, integrate different data composite methods, such as ACRIM, PMOD, and IRMB, and adhere to long-term TSI monitoring. In addition, use of cosmogenic nuclides such as 10Be and 14C in reconstructing TSI change caused by solar activity is also necessary to obtain long-period TSI series. By using cosmogenic nuclides, many historical TSI series have been reconstructed. Since the index of cosmogenic nuclides is an indirect record of TSI, we need to find out the records directly driven by TSI change. Explorations to other planets in the near future may provide a unique opportunity to resolve this issue. Currently, deriving historical TSI from celestial information such as lunar borehole temperatures has proved to be feasible. Furthermore, limitations of these methods should be noticed, and we need to improve the method of TSI reconstruction, so that we can get longer sequences and more accurate reconstruction of historical TSI. With the accumulation of long-term TSI monitoring data and progress in long sequence historical TSI reconstruction, we will obtain more and more detailed and reliable TSI series. It's important to objectively assess the impact of human activities on global climate change, and take effective measures accordingly to achieve the sustainability of earth surface system.

Key words: monitoring, reconstruction, research progress, solar activity, Total Solar Irradiance