To raise the bar 的意思就是“to raise the standard of quality”，“抬高标准”或者“提升水平”。单词“bar”在这里是名词，意思是“阻碍某事发生或发展的东西”。

例句

The golfer's record winning score raised the bar.

这位高尔夫球手获胜的分数破了纪录。

The singer's creative performances have raised the bar for other singers to follow.

这位歌手赋有创意的演出让后来的歌唱表演者很难超越。

Because so many students are achieving good grades, universities are raising the bar for students entering their universities.

因为有越来越多的学生都能取得很不错的考试成绩，所以各大学也随之抬高了他们的入学门槛。