Abstract: This article introduces the construction and trial operation of Shanghai Laser Electron Gamma Source (SLEGS) beamline, one of the Shanghai Synchrotron radiation Facility (SSRF) projects II, which can carry out basic research on nuclear physics and nuclear astrophysics, and applied research, such as gamma irradiation, gamma imaging and gamma activation. The SLEGS beamline passed the process acceptance in December 2021, entered the trial operation stage in October 2022, and have open to users in September 2023. SLEGS is the first Laser Compton Slant Scattering(LCSS) beamline in the world use the continuous collision angle mode to change the energy of the gamma beam, with the best ability of energy scanning accuracy, beam intensity and efficient energy regulation. In the trial operation stage, the SLEGS beamline station focused on solving the problem of online monitoring of gamma beam energy spectrum and beam intensity, mainly completed the experimental methodology research of photo neutron cross section measurement by Flat Efficiency Detectors (FED), and carried out the expansion and research of application platforms, such as gamma imaging, gamma activation and positron source generation. With the development of inverse Compton scattering techniques, short-pulse, high-polarization, high-intensity and miniaturized laser Compton scattering light sources will be in better development opportunities in the future, and will play an important role in nuclear physics, astrophysics, particle physics, polarization physics, as well as aerospace, medical testing, energy development and other gamma source application research fields.