The　effects　of　Nb　and　Ni　contents　on　the　precipitation　of　the　Ni16Nb6Si7-G　phase　and　the　resulting　hardening　behavior　in　Fe-20Cr　ferritic　alloys　were　systematically　investigated　using　micro-hardness,　electron　microscopy,　and　atom　probe　techniques.　The　results　demonstrate　that　an　optimal　Nb　content　of　similar　to　0.75　wt.　%　promotes　the　precipitation　of　the　Ni16Nb6Si7-G　phase,　leading　to　a　maximum　micro-hardness　of　approximately　430　H　V　when　aged　at　560　degrees　C　for　24　h.　Excess　Nb　content　(＞0.75　wt.　%)　introduces　the　Fe2Nb-Laves　phase　at　grain　boundaries　and　within　the　grains,　which　competes　with　the　G-phase　for　precipitation.　Conversely,　an　increase　in　Ni　content　effectively　raises　the　dissolution　temperature　of　the　Ni16Nb6Si7-G　phase　to　approximately　850　degrees　C.　The　austenite　phase　begins　to　form　when　the　Ni　content　exceeds　4　wt.　%.　Finally,　the　strengthening　effect　of　the　Ni16Nb6Si7-G　phase　and　its　underlying　competition　precipitation　with　the　Fe2Nb-Laves　phase　as　well　as　the　possible　benefit　of　inducing　austenite　phase　was　discussed　in　the　context　of　developing　20Cr　ferritic　alloys　with　high　strength　and　good　ductility.　These　findings　provide　valuable　insights　into　the　influence　of　Nb　and　Ni　contents　on　the　microstructural　evolution　and　mechanical　properties　of　the　newly　developed　20Cr　alloy,　which　may　be　helpful　in　guiding　the　design　of　high　performance　ferritic　alloys　by　optimizing　composition　and　heat　treatment　processes.