Large　quantities　of　electric　furnace　nickel　slag　(EFNS)　are　annually　generated　through　the　smelting　of　ferronickel　in　industries.　EFNS　contains　a　large　amount　of　glass　phase　SiO2　and　MgO,　with　certain　volcanic　ash　activity.　Nevertheless,　the　lower　early　activity　of　EFNS　due　to　the　ultralow　Ca　and　Al　greatly　limits　its　application.　To　descend　the　consumption　of　raw　materials　and　mitigate　environmental　pollution,　utilizing　such　wastes　as　a　binding　agent　in　the　domain　of　repairing　mortars　is　a　suitable　solution.　To　address　the　lack　of　Ca　and　Al　and　adjust　the　ratios　of　Ca/Al　and　Si/Al　in　EFNS-based　mortars,　the　purpose　of　the　research　was　to　incorporate　different　contents　of　slag　(SL)　and　fly　ash　(FA)　from　25%　to　40%,　respectively,　into　EFNS-based　mortars　activated　with　Na2SiO3.　The　study　involved　an　investigation　of　the　workability,　mechanical　properties,　bond　strength,　and　dry　shrinkage　of　the　mortars,　employing　different　percentages　of　SL　and　FA.　At　the　same　time,　TGA,　XRD,　MIP,　and　SEM　were　applied　to　investigate　the　chemical　composition　and　microstructure　of　the　binder　gel　phase.　The　results　showed　that　when　the　SL　content　reached　40%　and　the　FA　content　was　30%,　the　repair　performance　of　mortar　was　much　better　than　numerous　repair　materials,　with　an　excellent　compressive　strength　(94.0　MPa),　flexural　strength　(11.0　MPa),　and　bond　strength　(6.33　MPa).　As　such,　increasing　the　SL　and　FA　contents　seemed　to　have　a　positive　influence　on　dry　shrinkage　and　mechanical　strengths.　Additionally,　when　the　FA　content　was　30%,　the　incorporation　of　SL　was　found　to　promote　EFNS　hydrolysis,　and　the　hydration　could　directly　generate　hydrotalcite,　which　was　beneficial　to　decreasing　drying　shrinkage　at　28　d.　The　present　study　provides　a　theoretical　foundation　for　the　application　of　EFNS-based　geopolymers　in　repair　materials.