The study explores semantic and pragmatic characterics of russian particle ``ли`` and idiomatic phrases вряд ли, едва ли. Russian particle ``ли`` seems to present focus and modal meaning. Focus particle ``ли`` marks signal of question meaning, specially maker, which presents focus of sentence. From this, I can determine that the upper meaning of particle ``ли`` is question particle and focus particle. Also the study reveals that particle ``ли`` can play a role in modal meaning like surprise, assumption, impulse, doubt. Further, this paper attempt to present meaning mechanism ``вряд ли`` и ``едва ли``. Nagornyj argues that particle ``вряд ли`` presents reliability, whereas particle ``едва ли`` presents permissibility. But in this study it is argued that ``вряд ли`` and ``едва ли`` categorically cannot shared. Jespersen characterizes positive, negative and doubtful part as intermediate part. But in this study it is argued doubtful part close by negative part. Kalinina argues that particles вряд ли`` and ``едва ли`` tend to be presented as if more negative meaning than negative word with hypothetical adverb. Thus in this study it is argued that meaning mechanism ``вряд ли`` и ``едва ли`` is negative with doubt meaning.