A unique technology developed in our laboratory—pulsed laser irradiation scanning on mixed salt solutions (PLMS) to massively produce high-entropy nano-ceramics on various electrodes. We successfully demonstrate the electrocatalytic hydrogen evolution and oxygen production, working efficiently and stably in a seawater-like environment. Again, this high-entropy ceramic electrode is an excellent electrode suitable for a seawater-like environment. Including a very low onset voltage is 1.467V and great stability under 100 (mA/cm2) current operation for 1000 hours, furthermore, 400(mA/cm2) higher current run for more than 250 hours, which shows a great potential for industry application. These high entropy materials (AlCoCrFeMnNi)O and technology will make a great impact on the lower carbon emission. In addition, this study also clarifies each element role in our proposed (AlCoCrFeMnNi)O by taking advantage of the in situ measurement technology of the synchrotron radiation center