Accident　rate　was　selected　as　a　quantitative　indicator　and　hierarchical　standards　of　level　of　service　of　safety　(LOSS)　for　expressway　and　arterial　highway　were　studied,　and　then　the　LOSS　of　higher　highways　in　China　was　divided　into　4　levels.　In　virtue　of　the　probability　statistics,　robust　regression　and　on　the　basis　of　accident　data,　speed　limit　and　geometric　factors,　the　accident　prediction　model　was　established.　Based　on　the　acceptable　LOSS,　the　method　of　calculating　speed　limit　value　about　car　and　truck　was　got　respectively.　The　results　will　help　traffic　engineers　of　Chinese　highway　management　departments　in　choosing　reasonable　setting　method　of　speed　limits　for　higher　highways.