Abstract: The present disclosure provides a recombinant nucleic acid of Escherichia coli, a recombinant E. coli, a culturing method thereof, and a method for biosynthesizing L-threonine thereby, and relates to the technical field of bioengineering. The recombinant nucleic acid of E. coli of the present disclosure, including the gene encoding phosphoenolpyruvate carboxykinase (pck), the gene encoding pyruvate carboxylase (pyc) and the gene encoding threonine operon, is transformed into E. coli to obtain a recombinant E. coli LMT4 strain that takes glucose as a substrate. Using the LMT4 for fermentative production may significantly improve the L-threonine yield and glucose conversion rate, laying a foundation for the industrial production of L-threonine.