This study selects geochemical data of basalts from different seamounts in the Mid-Pacific Mountains province and conducts analyses of major and trace elements as well as Sr-Nd-Pb isotopes to explore the tectonic evolution, petrogenesis, and mantle-source magama characteristics of the Mid-Pacific Mountains. The basalts from the Mid-Pacific Mountains are predominantly alkali basalts, rich in alkalies, and changing in potassium. They exhibit geochemical features of ocean island basalts (OIB), with distinct fractionation between light and heavy rare-earth elements and a pronounced Ce negative anomaly (δCe = 0.16–1.10, average 0.84), along with enrichment in large ion lithophile elements (LILEs). The Mid-Pacific Mountains are intraplate ocean island basalts formed by mantle plume (hotspot) activity, originating mainly from an enriched mantle magma source region, and most of them have undergone low degree of partial melting and a certain degree of crystalline differentiation, with negligible contamination from oceanic crust materials. The Mid-Pacific Mountains exhibit ratios of 87Sr/86Sr(i) (0.702 733–0.704 313, average 0.703 452) and 143Nd/144Nd(i) (0.512 698–0.512 996, average 0.512846) which are close to the HIMU mantle end member, and ratios of 206Pb/204Pb (18.953–19.803), 207Pb/204Pb (15.54–15.62) and 208Pb/204Pb (38.813–39.514) which are close to the EMII mantle end-member. Combined with the isotopic geochemical characteristics in the West Pacific Seamounts province, the basalts from the Mid-Pacific Mountains were considered to represent a certain proportion of mixing mantle end-members between the HIMU and EMII, possibly formed by the mixing of the HIMU superplume in the South Pacific hotspot region with the EMII secondary mantle plume in the transition zone during their ascent.