Building a socialist rule of law state in Vietnam today is one of the most important and strategic political tasks, which has been consistently affirmed by our Party in the documents of the Party congresses since 1986 to present. Practice shows that, along with our achievements, the process of building our rule of law state also reveals some limitations in theory as well as confusion in practical activities. Therefore, studying the thoughts of democracy in the rule of law state of modern Western philosophy and its reference value for the expansion of democracy in the rule of law state in Vietnam today is extremely important. In that sense, with a methodology system of material dialectics, this article mainly clarifies some basic issues of the thoughts on democracy in early modern Western philosophy and applies the value of these thoughts to Vietnam today.