Coherent modulation imaging (CMI) based algorithm has been employed for on- shot laser beam diagnostics in high power laser facility and off- line measurement of large- scale optic element. A single- shot intensity measurement is sufficient for wave-front reconstruction after the random phase plate has been accurately pre- characterized, and the iteration process can be finished in 30 seconds with the acceleration of graphics processing unit (GPU) device. Furthermore, a compact structure is also available after combining CCD and phase plate together, which can be placed almost anywhere of high power laser facilities. Series of experiments have been finished for focal-spot prediction, measurement of large-scale continuous phase plate, and on-shot wave-front reconstruction of seed pulse in our high power laser facility with amplifiers turned off. The flexibility of CMI for focal- spot prediction, on- shot wave- front diagnostic and off- line measurement of optic elements has been demonstrated for its characteristic. It has significant influence on the development of high power laser facilities as a new method for wave-front measurement and diagnostics.