During the reign of his father Emperor Yang, he carried the title of Prince of Qi.
Yang Jian was considered handsome in his childhood, and Emperor Wen loved him.
In 599, Emperor Wen made him the head of the legislative bureau (Neishi Sheng, 內史省), one of the five main bureaus of government.
[2] In 604, Emperor Wen died—a death that traditional historians, while admitting a lack of direct evidence, generally believed to be a murder ordered by Yang Guang.
As a result, Yang Jian became arrogant, and he and his staff member often carried out illegal deeds, and he particularly liked to seize commoner women to make them his concubines.
Yang Jian's wife Princess Wei (韦妃) had died sometime ago, and Yang Jian then carried out an affair with her sister Lady Wei (韦氏) who had already married a man from the Yuan (元) clan.
One such reference was in spring 610, when a number of people claiming to be incarnations of the Maitreya Buddha entered into Luoyang and seized weapons, intending to attack the palace, but before they could do so, Yang Jian encountered them.
The troops did not respond, and they dragged Yang Jian and his two sons out to the streets and beheaded them.
Yang Zhengdao later returned to China during the reign of Emperor Taizong of Tang and was made Yuanwai sanqi shilang (员外散骑侍郎).