The collecting rain water was used as raw water in this experiment. The current density, electrified time, polar board spacing were changed in electro-coagulation process to search the optimum parameter for removal of raw water turbidity. The sequence relation of each factor one by one which affect the removal effect is current density>polar board spacing>contact time. When the current density was 18.89 A/m2, polar board space was 1 cm, contact time was 13 mins ,which is the optimum combination in electro-coagulation process of turbidity removal. Removal rate of CODMn and UV254 was improved in rainwater collection while the removal rate of turbidity was 92.94%.