In the paper the coupling impurities theory is used, and both s-d interaction effect and phonon effect in dilute magnetic alloys are discussed . The Green’s function is used to analyse the Hamiltonian of the system. In copper-iron dilute magnetic alloy the magnetic impurities interaction has a huge impact on thermoelectric power in the condition of high concentration of iron. Theoretic value of thermoelectric power of dilute magnetic copper-iron alloy with high concentration of iron changing with temperature is given. We have chosen three typical copper-iron dilute magnetic alloys and calculated the thermoelectric power under the effect of impurities and the effect of impurities interaction. Their atomic percentage concentrations are 0.1%, 0.13% and 0.15% respectively. Theoretical value of the thermoelectric power under the effect of impurities interaction in copper-iron alloy complies with experimental value. This paper provides the basic theoretical analysis for promoting the application of low-temperature copper-iron dilute magnetic thermocouple.