The invention discloses a machine tool machining precision reliability and sensitivity analyzing method based on a quick Markov chain.According to the method, a whole space error model of a machine tool is built through a multi-body system theory on the basis of a topological structure of the machine tool, and then the machine tool machining precision reliability is analyzed according to a quick Markov chain stimulation method; due to the fact that geometric errors of the machine tool are correlate to one another, firstly, the machine tool machining precision reliability is defined, seven failure modes of the machine tool are built, and the correlated geometric errors are converted into independent standard normal random variables; secondly, the failure probability of the machining precision is estimated through a reliability analyzing method for an independent space, and on the basis of a failure probability method for integral, machine tool machining precision reliability and sensitivity analyzing is achieved, and the main geometric errors influencing the machining precision reliability are obtained; lastly, the validity of the method is proved by taking a four-shaft machine tool as an example, and multi-shaft machine tool machining precision reliability and sensitivity analyzing can be performed through the method.