Distributed photovoltaic（DPV）access is beneficial to reduce the load peak and improve operation efficiency of distribution network. However

it is difficult to evaluate accurately the peak load efficiency due to its output uncertainty. In this paper

the PV output time-sequence model based on clearance model is set up through the analysis of PV output volatility and time sequence feature and

at the same time

considering the uncertanity of load and PV output

the confidence peak load index is proposed to measure the effect of PV access on the peak load of the distribution network. On this basis

a PLSB probabilistic evaluation method of distribution network with DPV considering uncertainty is proposed with combination of concept of locational marginal capacity cost of nodes. The real medium voltage feeder at certain distribution network in southern China is taken as an example for simulation and analysis and it is shown by the result that the method can

at the time of considering photovoltaic output uncertainty

accurately evaluate the peak load efficiency accessing to different positions and different voltage levels of the distribution network and have a definite significance for the location selection of distribution photovoltaic.