Optical method is a important method for soil moisture moisture measurement.Until now,theadaptability of the method to field soil is lack.In this paper,based on the variation data of field soilphysical and chemical characterstics,by analysing the variation of dielectric constant,refractive in-dex,the influnency of the soil bulk density and chemical composition,texture and temperature foroptical measurement method are struied;It was concluded that while soil bulk density and texturehave a rather effect upon optical mesaurement method,it is difficult to use the optical mesaurementmethod to determine soil moisture in the fields.