A nano grinding and dispersing assembly has a raw material feeder, a liquid supply unit connecting to the delivering pipe of the raw material feeder, a gas supply unit connecting to the delivering pipe of the raw material feeder, a pressure equalized assembly and a subsequent treatment plant. The raw material feeder has a feeding pipe connecting to the raw material feeder and a delivering pipe connecting to the raw material feeder. The pressure equalized assembly has a pressure equalizer, a pressurized feeding pipe, a gas-liquid separator, a pressure gage and a first grinding device. The first grinding device connects and communicates with the pressure equalizer and has at least one ground fluid outlet. The subsequent treatment plant connects the ground fluid outlet of the first grinding device. Therefore, the present invention completely mixes, grinds and disperses fluid to make the fluid homogeneous.