Thermal printing apparatus and printing methods thereof are disclosed. One of the proposed printing methods includes: providing an n-bit value corresponding to a pixel, wherein a color level of the pixel ranges from 0 to 2n−1; determining a total print time corresponding to a target bit of the n-bit value according to the bit significance of the target bit; and if the target bit is of a predetermined value, intermittently driving a heating unit to heat a ribbon within the print time corresponding to the target bit.