This paper introduces the main task of the fifth sub-topic project "Key Technologies in Laser Engineering and Cleaning Application" of the National Key Research and Development Project of the Ministry of Science and Technology (2017YFB0405100) from 2017 to 2021: the key technologies of quasi-continuous all-solid-state kilowatt level laser cleaner prototype. Laser cleaner prototype with three-dimensional large gantry frame forms laser cleaning industrial platform. A laser cleaning mechanism model for rail surface rust removal and aircraft composite skin paint removal is introduced. The methods of laser cleaning monitoring are introduced from sample identification, process monitoring and result detection. The laser cleaning parameters of 60 rail rust removal and aircraft aluminum skin depainting are obtained by author's research group, and the cleaning efficiency index passes the expert test. During the implementation of the project, developed prototypes are applied to more than 10 units such as China National Petroleum Corporation, Harbin Institute of Technology, Academy of Armored Force Engineering, Lianbo Heyi Technology Co., LTD. At the end of project execution, the project is awarded as the outstanding project of the key R&D plan of the Ministry of Science and Technology.