The project is expected to cost 83.7 billion yuan ($12.2 billion), partner Panjin Xicheng Industrial Group said in a statement on WeChat on Sunday.
Construction at the complex will start in the second quarter after the project secures the required administrative approvals, Aramco said.
Before the pandemic, Aramco signed two other initial agreements for refinery-petrochemical investments in China.
The other is with Shandong Energy that includes a potential crude supply agreement and chemical products offtake deal, as well as exploring collaboration on an integrated refining and petrochemical complex in China.
Earlier in March, Saudi Aramco also broke ground on a $7 billion project to produce petrochemicals from crude oil at its South Korean affiliate S-Oil Corp's (010950.KS) refining complex in the port city of Ulsan.