Through the addition of minor alloying elements, we have designed and prepared a new non-equiatomic six-membered Fe41Ni20Co20Cr10Al5V4 (at. %) high-entropy alloys (HEAs), with the aim of further improving HEA performance. The effect of annealing temperature on HEA microstructure and mechanical properties was systematically studied by using a variety of characterization methods. The results show that HEA Fe41Ni20Co20Cr10Al5V4 is a single-phase face-centered cubic (FCC) solid solution structure. The yield strength HEA Fe41Ni20Co20Cr10Al5V4 doped with minor element doped is 15% higher than that of the base alloy Fe40Ni20Co20Cr20 with a similar grain size while retaining good plasticity (elongation >50%). This can be attributed to the increased lattice distortion induced by the doping elements (i.e., Al and V). In addition, the strengthening mechanisms of Fe41Ni20Co20Cr10Al5V4 HEAs were analyzed. HEA strengthening mechanisms mainly include solid-solution strengthening, grain-boundary strengthening, and dislocation strengthening. Among them, in partially recrystallized HEA, fine-sized dislocation cells formed by the intertwining of high-density dislocations significantly increase material strength. Due to the excellent plasticity (~ 61%) inherent in HEA as-homogenized, further research can be carried to improve its strength with minimal compromise to plasticity in order to achieve a better balance between strength and ductility.