（1）The Bollinger Bands pattern characteristic at the starting position of an upward trend is that the bands contract to a historically low value for a certain period, the price rises above the middle band, followed by a strong upward breakout of the upper band, which causes the middle band to begin turning upward, and the Bollinger Bands start to open upward.
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（2）The Bollinger Bands pattern characteristic at the starting position of a downward trend is that the bands contract to a historically low value for a certain period, the price falls below the middle band, followed by a strong downward breakout of the lower band, which causes the middle band to begin turning downward, and the Bollinger Bands start to open downward.
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（3）At the early stage of an upward trend, when breaking above the upper band, the lower band moves downward, forming a trumpet shape that opens upward.
（4）At the early stage of a downward trend, when breaking below the lower band, the upper band moves upward, forming a trumpet shape that opens downward.
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（5）The Bollinger Bands pattern characteristic at the termination position of an upward trend is that the bands open to a historically high value for a certain period, the price falls from above the upper band to below the middle band, which causes the middle band to begin turning downward.
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（6）The Bollinger Bands pattern characteristic at the termination position of a downward trend is that the bands open to a historically high value for a certain period, the price rises from below the lower band to above the middle band, which causes the middle band to begin turning upward.
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（7）At the end of an upward trend, an M top pattern often appears, where the first peak breaks above the upper band, while the second peak typically rarely touches the upper band, forming a top divergence pattern.
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（8）At the end of a downward trend, a W bottom pattern often appears, where the first trough falls below the lower band, while the second trough typically rarely touches the lower band, forming a bottom divergence pattern.
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（9）In an upward trend, prices typically break above the upper band; in a downward trend, prices typically break below the lower band. However, this does not necessarily indicate a sell or buy signal.
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（10）The alternation of the opening and closing of the Bollinger Bands reflects a cycle of volatility; low volatility leads to high volatility, and high volatility leads to low volatility.
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（11）Combining Bollinger Bands with other indicators such as volume can improve the success rate of judgments. The derived indicators BB (Bollinger Limits) and WIDTH (Limit Width Indicator) can be used to establish trading systems.