A grayscale printing control method, a device thereof and a storage medium are provided. The method comprises: determining the grayscale level of image data of each point in each point line and converting the same into multi-bit binary data; forming a data set using the binary data of the same bit of all the points in a point line, thereby forming multiple data sets; each data set corresponding to a predetermined strobe time, and the print head heater corresponding to each point heating upon receiving predetermined data during the strobe time. The present invention can reduce the number of printing strobes and the times of data transmission while ensuring printing quality, thereby greatly improving printing speed.