Belonging to technical field of chemical product synthesis, the invention discloses a microreaction system and method for synthesis of anisole and derivatives thereof. The system is formed by connection of a microreactor, a heat exchanger and a phase separator in series successively. The synthesis method includes: mixing a sodium salt water solution of phenol or its derivatives and dimethyl sulfate in the microreactor and initiating reaction, controlling the product temperature by the heat exchanger, and performing separation by the phase separator to obtain anisole and derivatives thereof. The system and method provided by the invention can realize low-energy consumption and continuous production of anisole and its derivatives, improve the utilization rate of dimethyl sulfate, and can achieve a sodium phenolate conversion rate of 98% or more under the condition of a dimethyl sulfate/sodium phenolate mole ratio of slightly larger than 1.0, and the product purity reaches 99% or more.