The present disclosure provides a production method of a semi-aromatic polyamide, and a semi-aromatic polyamide. Said production method of a semi-aromatic polyamide includes: step 1 of subjecting an initial charge of a diamine and a binary acid in an amine/acid molar ratio of less than 1.0 to form a slurry together with water and a catalyst, and subjecting the slurry to heating and dissolution to form a saline solution; step 2 of dehydrating said saline solution after detecting the composition thereof, detecting the content of diamine in a steam condensate from a dehydration unit, adjusting the amine/acid molar ratio to be larger than 1.0 by a molten diamine and a monoacid as a molecular weight regulator, and performing pre-polymerization; and step 3 of subjecting a pre-polymerization solution to post-polycondensation after vacuum flashing. The semi-aromatic polyamide of the present disclosure has a low gel content, excellent performance and extensive scope of application.