Abstract: In order to compare the ecological effects of different plantations for various tree species and probe deeply into the differences in ecological service value among plantations, taking the 27-year-old long-term plantations in saline-alkali soils of the Yellow River delta as objects, the forest ecosystem service values of different plantations were revealed by calculating a suite of specific indices using formulae and prices of the Specification for Assessment of Forest Ecosystem Services in China (LY 1721—2008). The results showed that: the largest value of ecosystem service was velvet ash (Fraxinus velutina) plantation and the second one was black locust (Robinia pseudoacacia), i.e., 55717.76 and 49865.21 yuan/(hm2?a), respectively. The ecosystem service values of plantations for different tree species varied much following the order: velvet ash>black locust>Siberian elm (Ulmus pumila)>tree-of-heaven (Ailanthus altissima). 3 mixed plantations of black locust and velvet ash, black locust and Siberian elm, black locust and tree-of-heaven had the similar service values, which were lower than the pure one of black locust. Among 5 categories of ecosystem service, the largest proportion of ecosystem service value was water conservation, and the second one was carbon fixation and oxygen release. However, both atmospheric environment purification and biodiversity protection had relatively lower service values.