The invention discloses a synthetic method of a cadmium Schiff-base metal complex with anti-breast cancer activity. The synthesis route is simple, experimental condition is not rigorous, product yield is high, and a lot of high-purity crystals can be obtained. Repetition rate is 100%, compounds for experiment are easy to purify, and by-products are few and are easy to remove. The synthesized crystals have a stable structure and can be preserved for a long time. A solution (DMSO, etc.) prepared from the crystals has stable properties after detection of the compound, and also can be preserved for a long time. In comparison with the prior art, the product of the invention has better inhibitory activity values to cancer cells, and IC50 of inhibiting breast cancer cells can reach 2 and is better than IC50 of equal compounds.