The invention discloses glass ceramic and a float producing process thereof. The raw material of the glass ceramic contains calcium, and the total content of basic oxide is relatively high, the glass flattening and surface polishing can be carried out by means of gravity and surface tension of liquid glass in the production process, the glass is nucleated and crystallized stepwise in the heating process, and the glass ceramic with flat and smooth surface and excellent performance is finally obtained by controlling the nucleating temperature, the crystallizing temperature, the nucleating time, the crystallizing time and the amount of nucleating agent, and the problems of low yield, low production efficiency and high production cost in the glass ceramic production can be solved.