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This work is about understanding the r-process nucleosynthesis and chemical evolution of iron-peak element in the dwarf spheroidal galaxies. Neutrino-driven wind from proto-neutron star is regarded as one of the occasionswhere r-process and p-process take place.Solving Newtonian steady-state windequations, we investigate the effect of weak interaction rates on the dynamics andnucleosynthesis of neutrino-driven winds (NDWs) from proto-neutron stars (PNSs).For a typical 1.4 M☉ PNS model, we find the nucleosynthesis product with consideration of weak interactions are closely related to the luminosity of neutrinos andanti-neutrinos: the lower the luminosity is, the larger the effect is.At a low anti-neutrino luminosity of 1051 erg s-1 at the late stage of a NDW under the strong MFof a PNS, the weak interaction rates can enhance the mass of product and changethe physical properties of nucleosynthesis significantly.However for the most modelsconsidered for the NDWs from PNSs, based on our calculations we conclude that theinfluence of MFs on the net weak interaction rates and thus the nucleosynthesis isnot significant. Iron-peak element distribution in the dwarf spheroidal galaxies (dSphs) is important for research of the galaxy evolution and supernova (SN) nucleosynthesis.Nowadays, manganese (Mn) is one of the most observed iron-peak element for localdSphs.Modifying a phenomenological model recently proposed by Qian & Wasser(-)burg (2012) by including detailed calculations of supernova rates and yields in supernova explosions, we studied the chemical evolution of Fe and Mn in three localdwarf spheroidal galaxy (dSph) Fornax, Sculptor, and Sextans.We found that themodel can well describe the observed metalicity distributions in the three dSph galaxies(except a few sources in the dSph Sculptor), which indicates our model is generalreliable.On the other hand, the results indicate previous assumption of metellicity(-)dependant Mn yield of SNIa is not necessary as more core-collapse SNe models inwide mass range are considered.Our results predicted the distribution range of Mnin these dSphs, and provided theoretical basis for the further observations.Moreover,our method is feasible to the other iron-peak elements in the dSphs as well.