The real gradation of rockfill should be scaling on laboratory texts because of the limited size of apparatuses. The scaling will change the grading characteristics of rockfill，causing the scale effect and also exerts influences on texts. The scale effect of rockfill is influenced by many factors. The existing test results conducted by different researchers show different and even rever se trends. Based on existing researches， the influencing

factors including scale method， degree of compaction control standard， particle breakage， rock strength were summarized. The causes of such influences and the mesoscopic mechanism of rockfill scale effects were analyzed. Representative achievements and research progress were introduced. Relevant problems of scale effect were discussed. Th ese provide solid technical reserves for the design and build of high rockfill dam.