There is a linear logical relationship between public goods，state capacity and conflict resolution. State capacity is the guarantee of providing public goods，and a stable and fair supply of public goods by a government can significantly reduce the risk of domestic conflict recurrence. As an important public good of international security，the core logic of UN peacekeeping operations is that the root causes of conflicts can be fundamentally solved through capacity building of “fragile states”. So，can international public goods shape the state capacity of the state concerned to supply public goods？Through comparative analysis of two UN missions in the Democratic Republic of Congo found that the UN peacekeeping operations can better play a role of temporary public sector，but not qualified enough to shape the state capacity of the state concerned. The experience and lesson are that we should attach importance to a peaceful environment as a prerequisite for peace building，actively seek support from the countries concerned for peacekeeping operations，and define the limits of peacekeeping operations. On the premise of safeguarding its core functions，UN peacekeeping operations should actively explore a national development model based on the local knowledge of the country concerned.