In order to improve the construction technology level of the connection nodes of prefabricated hydraulic structures, and improve the mechanical properties, fluidity and economy of the connection mortar, this paper adopts the orthogonal experimental design to improve the cement mortar by adding polymer dispersible polymer powder. sex. A modified high-performance mortar with a compressive strength of 10 MPa, a fluidity of 90 mm and a final compressive strength grade of M25 was studied. The factors and levels of the orthogonal test are: mortar ratio 1:3、1:4、1:5; silica powder content of 4%、6%、8%; dispersible polymer powder content of 3%、5%、7%. After research, the optimal mixing ratio of modified high-performance mortar is 1:3, the content of silicon powder is 6%, the content of redispersible latex powder is 3%, the content of early strength water reducing agent is 0.1%, and the content of defoamer is 0.5%. The experimental verification is also carried out. This new type of modified high-performance cement mortar provides a new idea for the connection material of prefabricated hydraulic structures, which is of great significance for improving the integrity of prefabricated hydraulic structures and the durability of the connection.