The application relates to a
polishing method of a
quartz substrate and a
polishing liquid for
polishing the
quartz substrate, wherein the polishing method of the
quartz substrate adopts a double-sided polishing
machine to sequentially perform rough polishing and fine polishing on the
quartz substrate; a first polishing is performed on the
quartz substrate by using a rough polishing liquid, the rough polishing liquid is composed of first
abrasive grains, a first dispersing agent, a second dispersing agent and water, the first
abrasive grains are
cerium dioxide, the first dispersing agent contains
sodium salt and / or
ammonium salt, and the second dispersing agent has a different composition from that of the first dispersing agent; fine polishing is performed on the
quartz substrate by using a fine polishing liquid, the fine polishing liquid is composed of second
abrasive grains, a third dispersing agent, a fourth dispersing agent and water, the second abrasive grains are
cerium dioxide, the first dispersing agent contains
glycerol, and the fourth dispersing agent has a different composition from that of the third dispersing agent. The application can reduce the
surface roughness of the quartz substrate to below 0.2 mm, keep the flatness of the quartz substrate within 1 mu m, effectively improve the production efficiency, and easily clean the equipment after polishing.