The rockets are special products-variety much,but batch smaller.In this paper, little rockets how to be tested in a lager rocket thrust tester,that is how to widen the measure range of a rocket thrust tester, are presented and studied. It is pointed that the keys are how to install the rocket on a tester,ensure measuring accuracy and the calibration of the rocket thrust tester,the problems are studied in detail theoretically, the mechanical models are established,the measuring errors are analysed, and the steps to solve the problems are presented and demonstrated.As a result,it is pointed that any little rockets could to be tested in a lager rocket thrust tester,but the conditions are little frictions.