The effect of organic fertilizer composted by pig slurry on copper speciation in soil was studied via indoor pot experiment and BCR sequential extraction procedure. The fertilizer was added with CuSO4 and ZnSO4 to reach different concentrations of copper and zinc and applied with three application rates, 15, 30 and 45 Mg/hm2. The results showed that the application of organic fertilizer decreased the reducible fraction, increased in the oxidable fraction and a general inactivation of soil Cu. The application of fertilizer with high Cu content increased the acid extractable and oxidable fractions and consequently promoted the activity of copper. Simultaneously, there is a competition between Cu and Zn, in which Cu showed a stronger affinity with soil organic matters, Zn was more competitive in oxide bound fraction and could replace Cu in the reducible fraction.