【Objective】The present study was conducted to analyze the germplasm constitution of rice cultivars released in Heilongjiang province by estimating the genetic contribution of ancestor parents of released cultivars in order to provide important necessary information for cross design， enlarging parent sources and genetic base in rice breeding. 【Method】Based on the pedigree data of 191 rice cultivars released in Heilongjiang province during 1961-2006， the nuclear and cytoplasmic contribution rates of ancestor parents for each cultivar were calculated and analyzed， as well its germplasm geography and indica-japonica sources， and time-evolution characteristics. 【Result】The results showed that 191 cultivars released in Heilongjiang province for 45 years were traced back to 232 nuclear ancestors and the average nuclear ancestors was 15.8 for each cultivar， and the highest nuclear ancestors（43） were only found in one cultivar. More than 80% of released cultivars derived from fewer Japanese ancestors， about 47% derived from Guangdong landrace variety Lizhijiang of China， about 34% derived from Vietnam old variety Tadukang. The contribution rate of nuclear（cytoplasmic） germplasm from Japanese ancestors to Heilongjiang rice cultivars reached 62.00%（92.21%）， while those of nuclear（cytoplasmic） germplasm from Chinese ancestors was 31.81%（7.14%）. Considered on property of germplasm， the released cultivars in Heilongjiang had 93.055%（98.052%） of nuclear（cytoplasmic） germplasm from Japonica， 3.905%（1.948%） from indica and 0.002%（0） from wild rice. 【Conclusion】The germplasm sources of rice cultivars released in Heilongjiang province predominantly derive from Japanese，and have quite narrow genetic background in cytoplasm and lower effective utilization of indica and wild rice resources.