A reasonable design strength standard is of great practical significance for reducing pavement diseases. First, the bottom layer tensile stress of the typical pavement structure in the operating period is calculated using computer program BISAR while the overload、the interface link status and construction variability are all considered. And then the bottom layer tensile stresses of the upper and lower base are checked under truck load during construction. According to the relationship between cleavage strength (90d) and unconfined compressive strength (7d), it is deemed that the appropriate design strength standard should be 2.1MPa~3.5MPa. Finally, combined with the results of the unconfined compressive strength of core samples in the field it is proved that the current design standard is a little high.