The utility model relates to a highway protective facility technical field discloses a prevent block and guardrail for improve the protection safety nature of guardrail. Prevent block include relative setting and can with the guardrail backboard of guardrail side fixed connection's two curb plates, fixed connection the apron at two curb plate tops, and fixed connection two curb plates with the backplate of apron, wherein: the backplate has the strip -shaped slot who is used for with the stand joint of guardrail, the strip -shaped slot opening down. Receive the striking and when producing the slope when the stand, prevent that block and stand produce relative displacement along strip -shaped slot's length direction to the messenger prevents that block and stand take place to break away from, has improved the stand like this and to preventing that block applys the phenomenon of decurrent effort, has made to be difficult for receiving the effort and to appear buckling downwards with preventing the waveform guardrail plate that block is connected, has improved the protection safety nature of guardrail.