The invention discloses a method for preparing chlorine by carrying out hydrogen chloride oxidization by adopting a microreactor, comprising the following steps of: sufficiently mixing a gas flow vapor phase containing dioxygen with a gas flow vapor phase containing hydrogen chloride, and then preheating to the reaction temperature of 300-400 DEG C; introducing a preheated mixed gas to the microreactor to generate oxychlorination reaction under the action of a catalyst so as to generate the chlorine, and preheating the reacting mixed gas afterwards entering the microreactor by using heat released by the oxychlorination reaction. The method can effectively intensify the mass and heat transfer effect of two-phase catalytic reaction, shortens the time of the oxychlorination reaction, enhances the equilibrium conversion rate of the oxychlorination reaction and reduces the energy consumption of a production process.