How to use ADX in trading ???

The ADX identifies a strong trend when the ADX is over 25 and a weak trend when the ADX is below 20. Crossovers of the -DI and +DI lines can be used to generate trade signals. For example, if the +DI line crosses above the -DI line and the ADX is above 20, or ideally above 25, then that is a potential signal to buy.

The traditional setting for the ADX indicator is 14 time periods, but analysts have commonly used the ADX with settings as low as 7 or as high as 30. Lower settings will make the average directional index respond more quickly to price movement but tend to generate more false signals.

Many trading strategies like Linda Raschke's Holy Grail and Jeff Cooper's 5 Day Momentum Method use the ADX indicator to identify strong trends. However, day trading with the ADX indicator is not common. The reason is while the ADX indicator is good at identifying strong trends, it is a lagging indicator.