Taking quaternary red soil as the research object, TDR method, dry burning method and oven drying method were used to determine soil moisture in different gradients of different soil depth. Research results show that: measured value of dry burning method is relatively close to oven drying method, measured value of TDR is smaller than that of oven drying method, the absolute and relative deviations of the TDR method and dry burning method decrease with the increase of soil depth. The absolute deviation and relative deviation of the TDR method and dry burning method decrease with the increase of soil moisture content, and deviation of the soil moisture content is large in semi-humid conditions. The correlation of the TDR method, the dry burning method and oven drying method were 98.7% and 96.4% respectively. The results of this study confirm that TDR method and dry burning method can better reflect the soil water change law, and TDR method is smaller compared with the oven drying method, so it is necessary to calibrate to improve the accuracy before use.