The invention provides a carbon emission reduction calculation method and system for regional new energy power generation. According to the method, the fossil energy substitution amount, the fossil energy substitution rate, the carbon emission reduction amount and the carbon emission reduction rate are calculated by summarizing and counting the total electric quantity data and the total active power data of new energy power generation areas of different administrative regions, and the calculation results are visualized on a power grid GIS system map; a carbon emission reduction calculation system comprises a first system area, a second system area, a forward isolation device, a firewall and a third system area; the third system area comprises a statistical management module and a power grid geographic information module which are in network connection, a first area server is connected with the input end of the forward isolation device, the output end of the forward isolation device anda second-area server are connected with one end of the firewall, and the other end of the firewall is connected with the statistical management module; and the statistical management module comprisesa carbon emission reduction statistical unit, and the carbon emission reduction statistical unit is connected with a carbon emission reduction transaction platform through a network and repays and transfers the carbon emission reduction amount.