We proposed a patch-based metric to predict LCDs' realworld color performance. This metric takes 125 RGB patches for display and measurement. Generic image statistics, tone characteristics, weighted deltaE summary and the correlation to the general gamut mapping rules are taken into account in our metric. A visual test has been done for using its results to optimize the proposed metric. The metric is capable of predicting LCDs' color fidelity on 9 image types individually. It would be useful for LCD manufacturers to improve their produces.