Abstract: Through the use of reclaimed water as irrigation water source, a large high flower box was set up in the open field to carry out simulation experiment. The influence of different irrigation amounts on the desalting effect of coastal saline soil was studied, and the optimal irrigation amount was obtained through comprehensive evaluation. The irrigation amount was set as three treatments, respectively Z1 （512 mm）, Z2 （640 mm） and Z3 （768 mm）. The results showed that irrigation measures could directly and effectively reduce soil salinity under the experimental conditions, with a decrease of 22.83%~47.16%. The desalting rate from large to small was Z3> Z2> Z1, and the desalting rate increased with increasing irrigation amount. By taking desalting rate, soil salinity, soil moisture content and economic cost into consideration, and using the analytic hierarchy process for comprehensive evaluation, the optimal irrigation amount was 768 mm （Z3）, in order to provide reference for the application of reclaimed water irrigation and desalting engineering in coastal saline-alkali area.

Key words: reclaimed water, irrigation water amount, coastal saline soil, desalination effect, comprehensive assessment