LLD法、ROR法、差分法三种对时间序列消去趋势的方法。LLD法作用最强，其次是ROR法，最后是差分法。用于股票和期货序列。能用于任何用Excel写的时间序列。-LLD law, ROR method, differential method three time-series trends elimination. LLD law the strongest effect, followed by the ROR method, final difference method. Used to stock and futures sequence. Time series can be used in any written using Excel.