On December 13, 2022, the U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) announced that Lawrence Livermore National Laboratory (LLNL) first achieved the fusion output energy larger than the driving fusion laser energy by its National Ignition Facility (NIF), which was the “ignition” milestone in human history. The most considerable scientific breakthrough in decades provides significant support for national defense security and the development of clean energy. This article reports the interpretation of the difficulties of inertial confinement fusion (ICF) by interviewing professor ZHENG Wanguo, a senior researcher at the Laser Fusion Research Center of the Chinese Academy of Engineering Physics, including the paths to achieve “ignition”, the ignition process of laser fusion, the future development of ICF or inertial fusion energy (IFE), the important role of laser crystals in ICF or IFE and other issues of widespread concern. The professional information may help us to learn more about the development trend of ICF and IFE，and carry out the basic and key technology researches on crystalline materials to support the construction of laser drive devices in the future.