The invention discloses a method for efficiently preparing an environment-friendly gold leaching agent. The method comprises the following steps: enabling Salen-Na to react with FeCl3/Fe(NO3)3 to generate an efficient catalyst Salen-Fe(III); then uniformly mixing sodium cyanate, Salen-Fe(III) and an appropriate amount of pH adjustor and then reacting under the condition of 300-500 DEG C; and cooling to reach room temperature to obtain the environment-friendly gold leaching agent. The novel catalyst Salen-Fe(III) prepared by the method efficiently catalyzes preparation for the environment-friendly gold leaching agent, and reduces the activation energy of the reaction, so that a lower temperature needed for the reaction is achieved, and the energy consumption is saved; and the environment-friendly gold leaching agent is good in gold leaching effect, non-toxic and non-pollution, and environment-friendly and safe.