Abstract: Since the time-domain upscaling method will strengthen the border under the low bit rate significantly，and make quality much difference between Region of Interest（ROI） and background，this paper proposes a method based on time-domain transform for JPEG2000 ROI encoding.The original image is divided into two images based on the areas of interest and the background.Then both images are encoded into JPEG2000 in different output rates respectively.Finally，the two images are combined at the decoding part.This method also can be a supplement for the JPEG 2000 encode and decode system without ROI encode function.The experiment results show that，compared with time-domain method，this method not only significantly reduces the effects of borders，and ROI，BG and the PSNR area of the entire image are improved.