The present invention relates to a photovoltaic industry quartz square crucible spray coating machinery automation system and a process. The system comprises a spraying gun capable of spraying a slurry onto the inner surface of a quartz square crucible, a mechanical arm capable of clamping and moving the spraying gun and adjusting the spraying angle, and a rotation platform capable of installing and rotating the quartz square crucible, wherein a placing frame for placing the quartz square crucible and a stretching device are arranged on the rotation platform, the stretching device can pull and incline the placing frame to make the opening direction of the quartz square crucible and the top surface of the rotation platform form an elevation angle or pull and put the quartz square crucible in the correct position to make the opening of the quartz square crucible be laterally and outwardly placed. According to the photovoltaic industry quartz square crucible spray coating process, a slurry is prepared from silicon nitride, pure water and a silica sol according to a specific gravity of 1:1-1.5:0.2-0.5, and the slurry is sprayed onto the inner surface of the quartz square crucible. Compared with the system and the process in the prior art, the system and the process of the present invention have the following advantages that the system and the process are suitable for the square crucibles with various models in the photovoltaic industry, and have advantages of continuous working, simple operation, short time consumption, low energy consumption, high spraying efficiency, uniform coating thickness and stable quality; and the quality of the produced polycrystalline ingot is good after the crucible is sprayed, and the contact of the worker and the silicon nitride dust is not required during the spraying.