Abstract: To enhance volume rendering texture details and optimize the illumination effects, this paper presents a novel approach for adaptive pre-integrated illumination with minimum gradient angle. The extreme points of the sampled light are determined by directional derivative and spatial position. The rendering effect for extreme point region can be enhanced by the adaptive partitioning method. In order to highlight the sense of the object reality and enhance texture details, we introduce pre-integrated illumination algorithm in the paper. The calculation of color value of the pre-integral sampling section is based on minimum gradient angle algorithm. Then we can render the pre-integral sampling part. Experimental results show that, in contrast to the traditional pre-integrated method, our method can get better results where the scalar change greatly, and it can enhance the illumination effect for local details.