Structures and rheological behaviors of calcium phosphate gels depend on forming mediums and influence application properties. Objectives: To study the structure and strength of calcium phosphate gel by dynamic characterization of viscoelastic properties. These measurements help define the stability and effectiveness of potential remineralizing gels. Methods: A controlled stress rheometer was used to study the calcium phosphate gels with oscillation frequencies from 0.1 to 150 Hertz and a stress sweep from 3 to 256 Pa at 37 °C. The viscoelasticity, G*, and loss of tangent (tand) of the gel were continuously measured in a cup and bob measuring system. The gels were prepared in the cup by simultaneously adding highly concentrated calcium (1 to 5 mol/L) and phosphate solutions (1 to 6 mol/L with various pHs). Results: Gel with a maximum G* of 100k Pascal formed at pH 9.2 (with K2HPO4) and was stable throughout the stress and frequency sweeps. Weaker gels formed at lower (pH=7.5) and higher pH (pH=13). Gel with G* of 20k Pascal disintegrated at a sweep stress of 120 Pascal and 0.1 Hertz. Gel with G* of 10k Pascal disintegrated at a sweep stress of 40 Pascal and 0.1 Hertz and at a sweep stress of 30 Pascal and frequencies higher than 50 Herz. The phase angle d of the gels varied from 2° to 6°; the gel elasticity modulus was much larger than the viscosity modulus. Conclusions: The dynamic sweeps indicated that gels with higher G* contain more strongly associated calcium phosphate particles and have stronger internal structures. More strongly associated gels may provide a longer lasting improved remineralizing environment while weaker gels may spread and diffuse faster. Supported by NIST and the ADAHF.