The invention discloses a low-carbon power supply grid planning model considering carbon emission flow. A target function is shown in specification as follows, wherein Cy, Cy, Cy and Cy respectively express total investment construction cost, fixed running cost, variable running cost and regional connection line onstruction cost of a system in the y(th) year, the fifth item in the target function expresses carbon transaction cost, the Cy, the Cy and the Cy are described by investment problem, the Cy is described by running sub-problem, Y expresses all years to be planned, and r expresses inflation rate.