Photovoltaic generation does not consume fossil fuels and is free from carbon emission.Developing photovoltaic generation is an effective way of developing a low carbon electricity system.However，with its considerable randomness and intermittence，it brings new uncertainty to power system dispatch.This paper introduces the carbon trading mechanism to power system dispatch based on the concept of low carbon economy.A probability distribution model of solar irradiance and photovoltaic generation output is developed，and scenario reduction technology based on Kantorovich distance is used to reduce the photovoltaic generation output scenarios.On this basis，a model for power system optimal dispatch integrated with large scale photovoltaic generation and considering carbon trading cost is proposed.It has the advantage of balancing the economy，low carbon emission，and reliability of power system operation.A ten-unit test system is simulated via the proposed model to prove its rationality and effectiveness.