The invention discloses a preparation method of a carphosiderite catalyst, and the catalyst is combined with bioelectricity and
persulfate to establish a biological
electron-Fenton
system which is used for treating organic waste water. The carphosiderite catalyst is prepared mainly through the oxidization action of air by taking
ferrous sulfate as a precursor and adjusting the pH value, the preparation conditions are mild, the method is simple, and the prepared carphosiderite catalyst has the advantages of being high in activity, low in price, low in
metal dissolution and the like. When the biological
electron-Fenton
system taking carphosiderite as a catalyst is used for treating hardly-degraded organic pollutants in waste water, the treatment efficiency is high, the
energy consumption is low, and the
system can be conveniently operated and managed.