This paper presents mathematical models for monitoring mix-proportions of Chinese-standard concrete based on dielectric constant measurement. This technique is regarded as nondestructive nature with the meaning of early detection. The measurement makes use of microwave near-field probing technique while computer-aided measurement has been used. The devised models correlate the water-cement ratio (w/c) and the sand-aggregate ratio (s/a) with the measured dielectric constant in respective linear functions. The correlations of these ratios are also examined and the combined effect is found to be subtractive on the measured dielectric constant. As a result of this work, one can make use of these models to develop new diagnosis methods for the monitoring of accurate mix proportions by measuring the microwave permittivity of fresh concrete at early ages.