Disclosed are a method and an apparatus of re-cleaning, a cleaning robot, and a storage medium for improving cleaning quality. The method of re-cleaning includes: obtaining a grid map of a target area, wherein the grid map includes at least one primary cleaning partition; determining whether a primary cleaning partition meeting a re-cleaning condition is present, if so, the primary cleaning partition meeting the re-cleaning condition is designated as a re-cleaning partition to obtain at least one re-cleaning partition, wherein the re-cleaning condition is that the primary cleaning partition is provided with an along-wall mark and is not filled up by a cleaning mark; determining whether a re-cleaning partition that the cleaning robot can reach is present in the at least one re-cleaning partition according to a preset obstacle information database; and if so, navigating to a target partition for cleaning.