The invention discloses a process for producing modified starch by using a microwave far infrared method, comprising the following steps of: uniformly mixing starch with an oxidant, an acid/base catalyst, an etherifying agent and a esterifying agent, placing the mixture into microwave far infrared integration equipment for heating reaction, carrying out neutralization reaction and physical synergism, and finally sieving, weighting and packing. The invention has the advantages of high heating reaction speed, thorough reaction, good film-forming property, high bonding, enhancing and retaining ratio, low cost, wide application range, low energy consumption, no pollution to environment and scale production. The modified starch produced by the invention can be widely used as a binder, an intensifier, a stabilizer, a densifier and the like to be used in the industries of paper making, spinning, food, medical treatment, plastic, well drilling, building materials, daily chemicals and the like.