By significantly generalizing the work of Cartan to the case of hypersurfaces in Rn, he constructed a projective connection used in studying systems of differential equations known as the Hachtroudi Connection.
His subsequent research involved using intrinsically defined affine and Weylian connections to study the invariants of differential systems relative to different groups of transformations.
He was a Distinguished Professor at University of Tabriz and University of Tehran.
One of the Prizes of Iranian Mathematical Society is named after Professor Hashtroodi.Mohsen Hashtroodi married Robab Modiri in 1944.
They had two daughters, Faranak and Fariba, and one son, Ramin.
Professor Hashtroodi is buried in the Behesht-e Zahra cemetery in Tehran.