The invention relates to a constructed wetland treatment method of heavy metal wastewater from factories, comprising the steps as below: wastewater from workshops of metal processing factories flows into wastewater pools via water pumps; the wastewater containing heavy metal ions in the wastewater pools are pumped out and are sprinkled on the volcanic constructed wetland; the volcanic constructed wetland is internally filled with composite filling prepared by 5-30% of red soil, 3-30% of river sand, 5-75% of volcanic rock, 0.1-5% of nitrogen, 0.2-10% of phosphorus and 2-15% of potassium in terms of volume ratio. Water plants which can play good roles in absorbing the heavy metal ions are planted on the volcanic constructed wetland. After staying on the volcanic constructed wetland for more than 10h, the wastewater containing heavy metal ions are discharged from water pipes and purified; the purified water flows into water purifying tanks; the water in the water purifying tanks is supplied via water pumps as process water for the workshops of the metal processing factories to form water recycling. By the method, the heavy metal ions in the wastewater containing the same can be effectively absorbed.