In the 6 drying shrinkage indexes of 28 families of 10 year old Loblolly Pine wood of the radial shrinkage and volume shrinkage in oven and air dry conditions were all notable different at 0.01 remarkable level while the tangential shrinkage in oven and air dry conditions were notable different at 0.05 remarkable level. The results showed that the shrinkage of 16, 24, 27 and 32 family were lower among the 28 families. The variations of individual in a family were mostly higher than those among the families. These suggested that the effect of genetic improvement of forest tree could be better for individuals in a family. In addition, the oven and air drying shrinkage of wood from 28 families were closely correlated, e.g. tangential correlative coefficient was 0.8927, radial correlative coefficient was 0.8931, volume shrinkage was 0.8099, all of those reached a remarkable correlation at 0.01 level. The ratio between tangential and radial shrinkage （ T/R ）, the correlative coefficient in oven and air dry conditions was 0.8901 which also reached a remarkable correlation at 0.01 level.