Full-scale friction experiments of concrete block reinforced earth retaining wall between the block and geogrid are modeled on the special testing machine. The size of block which the interface of block and geogrid is the surface of 500 mm is 500 mm×500 mm×220 mm. The number of experiments is 96 and the laid dry and mortal masonry are divided. The force of friction，coefficient of friction and the influence factors are analyzed. The experimental study indicates that the force of friction increases with the vertical pressure increasing and the frictional connection reduces with the vertical pressure increased，but there are not linearity relationships，there are well logarithm relationships between force of friction and vertical pressure，coefficient of friction and vertical pressure respectively. The calculating result of a concrete block reinforced earth retaining wall with adjusted size of concrete block shows that the interval space decides the confine in which the frictional connection between block and geogrid can be used. The test results are useful for engineering practice.