Abstract: Aiming at the present situation of research and development of pullout test apparatus used to study the interaction between geosynethetic and soil at home and abroad,a large-scale pullout test system called CS-LB01 had been developed by Changsha University of Science and Technology combined with the expansive soil research project sponsored by the West Project Construction Office of Ministry of Communications of China.The characteristics of the test system were as follows: large scale sample can be tested;two test control methods including constant force control and speed control were alternated in the pullout tests on different soil samples and geosynethetic;the field condition were simulated.In addition,the loading method became more reasonable because air bags were set up on the surfaces and bottom of the box combining with the servo control loading system,and the influence of friction between test sample and both sides of box was eliminated.Furthermore,the test system was greatly improved by adopting high-precision force and displacement transducers and self-developed data acquisition system as compact and portable equipments.It was shown that the test system could be well used to simulate the realistic condition of reinforced expansive soil with geogrid,and to monitor the stress,deformation and the interaction between the soil and geogrid,then the acquisition of test parameters and the study on the reinforcing mechanism became more convenient.