Laser cleaning processing monitoring is essential to accurately remove the rust layer and effectively avoid the damages of the metal substrate. The variations between the number of cleaning and the rust cleaning rate at different spot overlap ratios on 30 mm×30 mm Q235B steel plate were studied by image processing to obtain the optimum spot overlap ratio of 50%. The changing trends of the Pearson correlation coefficient following the number of cleaning on 0.47 mm×0.47 mmQ235B steel plate were studied by Laser-induced Plasma Spectroscopy （LIPS） and the optimum number of cleaning was obtained under different thick dust layer. On this basis， the cooperation of image processing and LIPS is not only to dynamically correct the optimum number of cleaning but also to cover the shortage that image processing can not control the process of laser cleaning accurately. The results show that the cooperation of two methods can monitor the process of laser cleaning on a large area of Q235B steel plate and achieve high-quality laser cleaning with a 99.1% cleaning rate.