In studying the drying process by numerical simulation, the computational results of moisture must be validated by experiment. However, it was only validated by the value of the average moisture in the fruit, and was confirmed by the distribution value of the moisture. This in itself cannot validate the accuracy of the computational result and cannot yet provide important and valuable reference for improving drying techniques. To test the distribution of water in fruits, through experiment and analysis of the experiment result, the correlation between different points of moisture in fruit(apple) with the corresponding CT value on the CT image and the RGB value on the image with the corresponding CT value was found. The marked linear correlation between a point moisture of apple and its CT value exists, there fore every point of moisture in an apple can be found though the CT value or the RGB value at this point. It is a new way to test the moisture of different points in fruit.