Given the problem of system blocking caused by the traditional technology when processing big images and redrawing user interface, we propose an improved three level buffers technology. Firstly, a memory area compatible with the properties of the big image is allocated to load the big image data. Secondly, another allocated memory area compatible with the display device is used to execute other image processing instructions. Finally, the image data is copied to the real display device by the bit-block-transfer method in sequence. So only the memory area compatible with the display device is released and another memory area can avoid reloading the image when redrawing the user interface. The proposed technology is proved to be effective when processing the big drilling histogram in the digital core system software.