The invention discloses a preparation method and application of eclipta extract. The preparation method comprises the following steps of: 1) selecting eclipta, soaking for 0.5 hour with ethanol water solution with the volume percent concentration of 5-95%, extracting for 1 hour when the weight of the ethanol water solution is 20 times of the weight of eclipta and extracting for 0.5 hour when the weight of the ethanol water solution is 16 times of the weight of the eclipta, mixing extracts together, concentrating the extract into 0.25-1.0g crude drug/ml, standing for 6 hours, and filtering to obtain the eclipta extract; and 2) adsorbing the eclipta extract by adopting pretreated macroporous resin, wherein the weight ratio of the eclipta extract to the macroporous resin is 1:1-1:5, feeding flow rate is 1-3BV/h and the diameter height ratio of the resin is 1:4- 1:7, washing for 3-6BV with water after adsorbing, wherein eluting flow rate is 2-4BV/h, throwing away eluent; eluting for 3-6BV with the ethanol water solution with the volume percent concentration of 20-90%, wherein the flow rate is 2-4BV/h, collecting the ethanol/water eluent, concentrating, and drying to obtain the eclipta extract. By adopting the preparation method disclosed by the invention, purification cost is reduced, industrial production is easy to realize, and no environment pollution is caused.