Abstract: In the present paper an attempt was made to introduce Kalman's Linear Filtering and to apply it to the continuative forest inventory.Two estimated values of the linear filtering were used to estimate the changes of forest resources.One was the difference between two elements of flitering vector,i.e,flitering difference;the other was the difference between two estimators on two occasions.The former was more accurate than the latter,but the latter,is more suitable for maintaining the two estimators to be consistent.In addition,the formula of linear filtering,which was used in the various SPR projects of continuative forest inventory on the two occasions,was given and some associated problems were also discussed based on the results of forest inventories made in a forestry bureau of Jilin Province.