The reliable year of King Wu conquered over Shang Dynasty is an important year in Chinese ancient historiography. Recently, the technique of 14C dating has been greatly improved, and the possibility of distinguishing the year of King Wu conquered over Shang Dynasty using 14C dating was discussed in conferences, some pre-research works performed. Since 1996, the program Xia-Shang-Zhou chronology project has put into practice, our team began to take part in the study of above chronological problems. In early 1998, the samples collected from Fenghao site, Shanzi province, China, were determined in two conventional 14C laboratories with the measuring error are less than 3%. On October 6th and 7th, the results were announced successively that the year of King Wu conquered over Shang Dynasty were distinguished in the period of B.C. 1050 to B.C. 1020. In later 1998, the AMS 14C laboratory began dating too. The results of three 14C laboratories are identically with each other. 14C dating of the samples unearthed from tombs at Yinxu site, and Liulihe site and wiggle-matching with curve together reached the results that the boundary years coincided with the year range determined above. On November 30th 1998, the result by astronomical calculations were announced, the year of King Wu conquered over Shang Dynasty located also in the age range by 14C dating. From early 1998 to March 2000, almost during two years, the age range distinguished by 14C dating had been examined many times. At last, the results would be trustworthy acknowledged.