With the development of smart grid, and large-scale clean energy generating systems integrated within load center, problems like concatenate off-network accident and network voltage level fluctuation stands out, posing huge challenge to the safe operation of power system. As the thorough extension of safety problem in power system, the assessment of power grid running state has significant research value. This paper use system operating parameters, propose assessment model and index of load nodes running state, based on short circuit capacity theory, that is to compare the needed short circuit capacity of load nodes and total short circuit capacity provided by system and connected power source, and evaluate the running state of load nodes rapidly. This method takes the access of clean energy into consideration, and discuss the effect of different power source to power grid running state, by comparing obtained nodes running state, perfects running state evaluation system, and are available for online evaluation, providing decision support. At last, this paper verifys the effectiveness and superiority of this method based on simulation result of IEEE-30 nodes system.