Using the principle of saponification reaction, a new fatty acid salt thixotropic agent was developed by investigating the effects of solvent content, alkali content and kinds of oils and fats on the thixotropic of cement paste.The rheological properties and constant torque in different periods were tested.The result shows that, the cement paste has outstanding thixotropy when incorporating new thixotropic agent. The cement paste is in relatively steady state when it is allowed to stand, but when a special shear stirs the cement paste, it is in a fluid like state. The fluidity of cement paste is very stable.