Research the quantitative evaluation of the renewable energy in distribution network. First of all, establish the optimization model to calculate the best output power consumption of renewable energy units. Taking into account the local unit output ceiling, load level, grid structure, power flow as well as other constraints, making the renewable energy unit output as large as possible, the consumption as low as possible while the profits as high as possible. Secondly, define the assessment indicators and analyze them around the index. Evaluate the results of comparison on the results of the optimization model with the actual power. Based on the indicators, the consumption capacity involves the power grid economy, security and inherent characteristics of the system. Finally, an explicit expression of the index is derived from the solution without using the conventional iterative algorithm. The rationality, simplicity and operability of the index are given.