The invention provides a method for preparing copper powder through the micro-reaction. The method comprises the following steps that a dispersing agent is added in a copper compound water solution, stirring is conducted, then the water solution is heated to 35-85 DEG C, and a solution A is obtained; a reducing agent, alkali and deionized water are mixed and stirred, and then are heated to 35 DEGC-85 DEG C, and a solution B is obtained; the solution A and the solution B are added in a microreactor react, the temperature in the microreactor ranges from 35 DEG C to 85 DEG C, and an ultrasonic device in the microreactor is started; a reacting solution in the microreactor flows into a storage container with ultrasonic stirring, antioxidant is added in the storage container, an ultrasound device is started, stirring is conducted, and sufficient mixing is conducted; and then, liquid-solid separation is conducted, washing is conducted, and after vacuum drying, separation is conducted throughan airflow classifier, and a copper powder product is obtained. The copper powder obtained through the technical scheme has the beneficial effects that the grain size of the copper powder is small, the copper powder is in a sphere or sphere-like shape, and oxidization resistance is high; and the technology process is short, cost is low, amplification is easy, and waste gas and waste slag are avoided.