The disclosure provided a compressing method of the grayscale compensation table of an OLED display panel, which comprising: step 10, when transmitting a set of grayscale compensation table of the OLED display panel to an encoder for encoding, firstly, performing a differential calculation on many grayscale compensation tables with a same color channel and different gray scales in the set of which to acquire a corresponding reference image and a difference image as replacements of many grayscale compensation tables; step 20, transmitting the above images to the encoder; step 30, the encoder compressing and encoding a received grayscale compensation table. The compressing method of the grayscale compensation table of the OLED display panel performs the intra-level differences between the same color component and the different grayscale compensation tables in the same OLED compensation table to improve an efficiency and a performance of the compression compensation table.