The metallographic microscopy, scanning electron microscopy and energy-dispersive spectrometry (SEM-DES) were employed to investigate the bronzes of early period of Western Zhou dynasty (11th-8th BC) excavated from Yu Jia-wan, Gansu Province. Among the sixteen bronze artifacts, there were five tin bronzes, eight lead-tin bronzes, one lead bronze, one arsenic lead bronze and one iron lead bronze. Four basins were forged, and another one basin was cast then heated incompletely. Other twelve bronzes have the casting microstructure. These four basins are the earliest forged containers that have been examined so far in China. The results provided a large number of important and useful information to the archaeologists.