The invention discloses a novel technology for efficiently producing furfural and simultaneously recycling by-products including methanoic acid and acetic acid. An impinging stream reactor which is especially suitable for the technology is adopted, fluid mixing is achieved through multiple times of impinging, a good micromixing effect is achieved, mixed liquid flows outside an impinging area in a plug-flow mode, sufficient staying time is provided for materials, cascaded reacting is achieved, and the target conversion rate is achieved through flow channel and liquid flow rate design. According to the technology, the defect that an existing impinging stream reactor cannot achieve the high conversion rate through a single reactor is overcome, the technology procedures are simplified, production cost and equipment investment are reduced, and long-period running of equipment is guaranteed; no waste liquid is drained in the production process, and a green and environment-friendly technology method is achieved.