Abstract: In the April of 2010, gold displacement rate was 1.8 %, which is lower than the usual. After the analyses of gold fluid and cyaniding gold mud, it was discovered that lead's content was going up. After test analyzing, the chief factor of gold displacement rate decreasing was that the zinc powder consumption amount was too low. Upon finding the reason, the gold displacement rate returned to usual level by adjusting the technique parameters of zinc powder displacement.