The compatibility between underwater-washout admixture(AWA) and two different types of superplasticizers, polycarboxylate-type and naphthalene-based, was studied. The results showed that, there were different compatibilities between AWA and different superplasticizer, but the differences were not apparent. Compatibility of AWA with polycarboxylate superplasticizer was better than that of naphthalene superplasticizer. When the solid content is same, the difference of compatibility between AWA and different brand polycarboxylate-type superplasticizer was very slight. The underwater concrete with good anti-washout performance, good fluidity, self-compacting ability and corrosion resistance can be prepared easily through the reasonable compound. However it was difficult to solve the retarding problem and the contradiction between good fluidity and strength of the non-dispersible underwater concrete.