The feasibility of low-frequency ground-penetrating radar (GPR) in measuring soil water content by using ground wave technique was investigated in order to provide a new method for soil water content measurement in small-scale region. Water contents of sandy loam and sandy soils with GPR ground wave technique were measured in Huang-Huai-Hai Plain. Antenna separations of GPR were 50 MHz and 100 MHz respectively. The results showed that ground wave can neither be interpreted in sandy soil nor sandy loam with 50 MHz antenna and in sandy loam with 100 MHz antenna due to the strong attenuation of the GPR signal, but can be clearly read out in sandy soil with 100 MHz antenna. Sandy soil water content measured with 100 MHz antenna GPR ground wave techniques were 5.9%, 6.2% and 6.5% respectively for three replicates, while 6.3% with TDR measurement, absolute error was within 0.4%. Soil water content before and after irrigation were 6.5% and 20.2% respectively determined by CMP-FO (the combination of Common Mid-Point and Fixed Offset ) method and were 6.3% and 19.7% respectively by TDR, the absolute error was within 0.5%. CMP-FO method is accurate and time-saving, it is feasible and credible to determine soil water content in arid area with 100 MHz antenna GPR.