追蹤止損單有下列三點用途：
• 限制你的損失；
• 保護你的盈利；
• 防止你因為錯誤信號而提前進入（或退出）交易。
止損可以基於每天交易價格波動的最高點或最低點設置，或根據距離交易底部距離的百分比設置。J.威爾斯.韋爾德的抛物線轉向指標（SAR）是追蹤止損的進一步發展。
下列原則是建立在亞歷山大埃爾德在《以交易為生》一書中描述的三重濾網交易系統的原則之上。
止損買進
當你得到一個做多的信號——在該信號上方一個點處設置買入指令。如果價格反彈，那麼你將能夠順利進場做多；如果價格回落，那麼買入指令將不會被觸發。你可以將買入指令逐漸下移到接下來一天的高點處直到買入指令被觸發。進場之後，在最低點處設置止損（得到交易信號之後價格波動的最低點）。
止損賣出
當你得到一個做空的信號——在距離當天價格的最低點一個點處設置賣出指令。如果第二天價格突破該低點，你將成功進場。如果價格反彈，那麼做空指令將不會被觸發。接下來幾天根據最低價不斷的調整做空的價位（位於當天價格最低處一個點位置），直到成功下單。之後，你需要在得到交易信號之後價格的最高點處設置止損。
例：
下圖顯示的是英特爾公司 21 天指數移動平均線和7日隨機指標 K值、 D值。
1. K值在[1]處下降到20以下，可在當日的最高價格（$33 1/2）上方一個點處挂一個追蹤止損買入單。
2. 價格在[2]處最高價為$33，沒有觸發買單。將止損買入挂單下移到$33上方一個點處。
3. 止損買入向下移至[3]下方一個點處。
4. 在[4]處將止損買入價移到$32 1/2 。
5. 價格在[5]處達到新低 $31 3/8 ，向上越過止損買入價位$32 1/2。 選擇[1]~[5]價格區間的最低處設置追蹤止損。
日内波動
當接下來的幾天K線沒有突破新高或新低時，止損挂單就不會相應的被調整。
如果價格沒有走出新低，那麼止損買入價位就不會調整；
如果價格沒有出現新高，那麼止損賣出也就不會被調整。
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.
本文翻譯由兄弟財經提供
本文來源：http://www.incrediblecharts.com/trading/trailing-stop-loss-order.php