Firstly, the price of the underlying securities in a fixed period of time (usually the daily closing price or average price) is obtained from the market; Then, for each time period, find the natural logarithm of the ratio of the stock price at the end of the time period to the stock price at the end of the previous time period; Then, calculate the standard deviation of these logarithmic values and multiply it by the square root of the number of time periods included in a year to get the historical volatility. Calculated by this method and adjusted, the volatility of Guodian Power Warrant in the year before listing is assumed to be 35% (adjusted after taking the closing price of 242 trading days from July 13, 2005 to July 14, 2006 as the observation sample). Many market statistics software will reveal the historical volatility of securities, and investors generally do not need to calculate it themselves.