追踪止损单有下列三点用途：
• 限制你的损失；
• 保护你的盈利；
• 防止你因为错误信号而提前进入（或退出）交易。
止损可以基于每天交易价格波动的最高点或最低点设置，或根据距离交易底部距离的百分比设置。J.威尔斯.韦尔德的抛物线转向指标（SAR）是追踪止损的进一步发展。
下列原则是建立在亚历山大埃尔德在《以交易为生》一书中描述的三重滤网交易系统的原则之上。
止损买进
当你得到一个做多的信号——在该信号上方一个点处设置买入指令。如果价格反弹，那么你将能够顺利进场做多；如果价格回落，那么买入指令将不会被触发。你可以将买入指令逐渐下移到接下来一天的高点处直到买入指令被触发。进场之后，在最低点处设置止损（得到交易信号之后价格波动的最低点）。
止损卖出
当你得到一个做空的信号——在距离当天价格的最低点一个点处设置卖出指令。如果第二天价格突破该低点，你将成功进场。如果价格反弹，那么做空指令将不会被触发。接下来几天根据最低价不断的调整做空的价位（位于当天价格最低处一个点位置），直到成功下单。之后，你需要在得到交易信号之后价格的最高点处设置止损。
例：
下图显示的是英特尔公司 21 天指数移动平均线和7日随机指标 K值、 D值。
1. K值在[1]处下降到20以下，可在当日的最高价格（$33 1/2）上方一个点处挂一个追踪止损买入单。
2. 价格在[2]处最高价为$33，没有触发买单。将止损买入挂单下移到$33上方一个点处。
3. 止损买入向下移至[3]下方一个点处。
4. 在[4]处将止损买入价移到$32 1/2 。
5. 价格在[5]处达到新低 $31 3/8 ，向上越过止损买入价位$32 1/2。 选择[1]~[5]价格区间的最低处设置追踪止损。
日内波动
当接下来的几天K线没有突破新高或新低时，止损挂单就不会相应的被调整。
如果价格没有走出新低，那么止损买入价位就不会调整；
如果价格没有出现新高，那么止损卖出也就不会被调整。
Trailing Stop Loss Orders
Trailing stop loss orders have three uses:
• To limit your losses,
• To protect your profits, or
• To prevent you from entering (or exiting) a trade too early or on a false signal.
Stops can be based on the high/low of the daily trading range or on a trailing percentage. Welles Wilder'sParabolic SAR is a further form of trailing stop.
The rules below are based on Screen 3 of the Triple Screen trading system, described by Alexander Elder inTrading for a Living.
Buy-Stop
When you get a signal to go long - place a buy order one tick above the High on the signal day. If price rallies, you will be stopped in on the next day. If price falls, the buy order will remain untouched. Move the buy order down to one tick above the High on the second day. Continue to lower the buy order on each subsequent day until price rallies and you are stopped in.
When you are stopped in, place a stop loss below the Low of the recent down-trend (the lowest Low since the signal day).
Sell-Stop
When you get a signal to go short - place an order to sell short one tick below the Low on the signal day. If price falls, you will be stopped in on the next day. If price rallies, the buy order will remain untouched. Move the sell-stop up to one tick below the Low on the second day. Continue to raise the sell-stop on each subsequent day until there is a correction and you are stopped in.
When your sell-stop is executed, place a stop loss above the High of the recent up-trend (the highest High since the signal day).
* Day 4 makes a new High and a new Low. If the High was made before the sell-stop is reached, the stop-loss will be placed as shown. If the sell-stop was activated before the new High was made, then the stop-loss would have been placed above the High of Day 3 and the trade would have been stropped out on making the new High.
EXAMPLE
Intel Corporation is shown with a 21 day exponential moving average and 7-day Stochastic %K and %D.
1. %K falls below 20. Place a trailing buy-stop just above the day's High of $33 1/2.
2. Move the buy-stop down to $33, above the High of day 2.
3. Move the stop down to above the High of day 3.
4. Move the stop down to $32 1/2 - one tick above the High on day 4.
5. The day opens with a new Low of $31 3/8 and then rises until we are stopped in at $32 1/2. Place a stop-loss below the Low (i.e.. the lowest Low since day [1]). Thereafter, price falls back to the day's Low, but fails to activate the stop-loss one tick below.
Inside Days
The rules for sell and buy stops are sometimes varied by excluding inside days:
• no adjustment is made to a buy-stop if the day does not make a new low;
• no adjustment is made to a sell-stop on days that do not make a new high.
本文翻译由兄弟财经提供
本文来源：http://www.incrediblecharts.com/trading/trailing-stop-loss-order.php