1. Operation method of fixed fund investment in Huatai Securities online trading system: after logging in to the trading system-enter the personal account-click on the fund in the lower left corner-you can find the fixed fund investment. 2. Fixed investment is the abbreviation of fixed-term investment fund, which means that a fixed amount (such as 500 yuan) is invested in a designated open-end fund at a fixed time (such as the 8th of each month), which is similar to the bank's deposit and withdrawal method.