Method for preparing methyl formate and coproducing dimethyl ether by reacting a formaldehyde and methanol raw material (molar ratio range of 1:4 to 1:0.05) in a First Reaction Region at ranges from 50° C. to 100° C. with Catalyst A resulting in post-reaction material separated into Constituent I. Reacting Constituent I in a Second Reaction Region at ranges from 50° C. to 200° C. and from 0.1 MPa to 10 MPa with Catalyst B resulting in post-reaction material, which is separated into methyl formate, dimethyl ether and Constituent II. At least 1% of dimethyl ether is product, and recycling the rest to the First Reaction Region. Constituent II is recycled to the Second Reaction Region. Each component is gaseous phase and/or liquid phase, independently. The method shows long catalyst life, mild reaction condition, high utilization ratio of raw materials, continuous production and large scale industrial application potential.