Sun Zhang 孫璋 was a eunuch and a favourite of Emperor Ling of Han. During the 180's he and eleven other eunuchs were made Regular Palace Attendants and enfeoffed as full marquises. Sun Zhang may have sided with the corrupt eunuch faction led by Zhang Rang 張讓 and Duan Gui 段珪.
Historical sources don't share much information on the eunuch Sun Zhang. In the sixth lunar month of 185 AD, which is late July or early August, Sun Zhang and eleven other eunuchs were enfeoffed as full marquises for their good work against Zhang Jue 張角 and the Yellow Turbans. After this, Sun Zhang is not mentioned again. It is possible that Sun Zhang was part of the eunuch group which waylayed and killed the General-in-Chief He Jin and that he died in the eunuch slaughter afterwards.
- Sun Zhang's date of death is not mentioned in historical sources, but it's safe to say he died in the eunuch massacre in 189 A.D. along with all other eunuchs.