Abstract: Amid the fast increase of global population and the quest for sustainable agriculture, the need for enhanced rice breeding strategies has become increasingly pronounced, particularly in Heilongjiang, China's foremost rice-producing province, renowned for its premium temperate japonica rice. Here, we conducted an extensive genomic investigation of the elite rice cultivars developed in Heilongjiang Province. Using whole-genome re-sequencing of a total of 376 representative cultivars from Heilongjiang, of which 14 were developed by a single research group, we identified 4.9 million SNPs and 0.98 million InDels, offering a comprehensive perspective on genetic diversity and population structure. We classified the 376 rice cultivars into five subgroups based on their breeding years. Recently bred cultivars, assigned to subgroups HLJ-IV-1 and HLJ-IV-2, showed notable genetic differentiation. Through a selective sweep analysis, significant genomic variation in genes such as OsACBP5, Os4CL5, and GFR1 was pinpointed, reflecting a concerted effort in selecting for broad-spectrum disease resistance and enhanced tillering capacity. Furthermore, to identify the strengths and areas for improvement within those series, we conducted an exhaustive analysis of aromatic compounds and their corresponding genes OsODC and OsBadh2, as well as the the advantageous long-grain gene OsGL3.1 haplotype within Hagengdao7. Additionally, strategies for reducing plant height through the introduction of the sd1 gene were elucidated. With a commitment to expediting the development of superior rice cultivars, our discoveries are poised to raise the sensory attributes and nutritional profile of rice, thereby bolstering the resilience and sustainability of global food systems.