The influence of water binder ratio, content of borax and fly ash on the fluidity and strength of phosphate concrete were investigated. Results showed that the slump and slump flow of phosphate concrete improved with content of water and borax increasing. But the strength decreased, especially early strength. While the mixing amount of borax was less than 1.5% of the magnesium phosphate cement, the influence on later strength was relatively less. The fluidity decreased significantly and the cohesiveness and water retention improved while the content of fly ash was between 10% and 30%.The compressive strength increased while the content of fly ash was 10%.The better curing methods was curing in the natural conditions, the compressive increased with the age prolonged.