The invention provides a JPEG 2000 area-of-interest coding method based on pre-truncation. The method is located between small-wave conversion and bit-plane coding in a JPEG 2000 system and suitable for application occasions with unimportant given code rates or backgrounds. By means of the method, more code streams are distributed to areas of interest by properly lowering the background coefficient accuracy, and the method is excellent on the aspects of coding quality of the areas of interest, system computing amount and the like. The method includes the steps that 1, a code rate searching table is established under a specific application occasion; 2, an area searching table is established under the specific application occasion; 3, the code rate searching table and the area searching table are indexed through the code rate and the area of the areas of interest, and the output sum of the two searching tables is computed; 4, the boundaries of the areas of interest in all small wave sub-bands are computed according to the position of the areas of interest in an original image; 5, background coefficients are pre-truncated.