With the rapid development of the economic system and the continuous development of industry, environmental pollution is becoming more and more important, so wastewater treatment urgently needs to be strengthened. This article uses fly ash-coated iron electrode electrocoagulation method to carry out experimental tests on the treatment of comprehensive wastewater from chemical and pharmaceutical parks. Fly ash is used as a raw material to prepare a shaped adsorbent; in order to analyze whether the adsorbent has many potential applications in actual wastewater treatment and use. The experiment research of iron electrode electrocoagulation was carried out on actual groundwater, aiming to provide data and theoretical support for the utilization of fly ash and the optimization of comprehensive wastewater treatment technology. The article mainly conducts related research on title distribution, firstly the physical and chemical properties of fly ash, and secondly, discusses the related structure of electrocoagulation method, and solves the problem of comprehensive wastewater based on the combination of the two solving issues. Aware of the importance of sewage treatment and the characteristics of related treatment methods such as adsorption, membrane separation technology, and ion exchange, the advantages of these methods are also used for reference in subsequent experiments to achieve the purpose of reliable experimental results. The experimental results show that the effect of sewage treatment with fly ash with different average diameter particles is obvious. Among them, the maximum value of vibration grinding ash before and after application increased from 5.62 to 8.31, and the maximum removal rate is also 8.31; the removal effect is significant. It can be seen that the fly ash-coated iron electrode electrocoagulation method can have a great effect on the treatment of comprehensive wastewater in the chemical and pharmaceutical park.