The　voltage-stabilized　generator　for　Measure　While　Drilling　is　used　in　the　oil　drilling　steering　system.　This　kind　of　generator’s　design　requirements　include　voltage　regulation　range,　power　generation　and　the　slender　design　space.　Base　on　the　axial/radial　magnetic　hybrid　excitation　synchronous　generator,　we　propose　a　voltage　stabilizing　generator　structure　of　hybrid　excitation　with　slender　salient　pole　which　called　SSP-HEG　which　is　composed　of　hybrid　excitation　and　permanent　magnet　synchronous　generator.　The　magnetic　circuit　paths　are　analyzed　by　electromagnetic　field　finite　element　method.　The　length　of　the　permanent　magnet-salient　pole　hybrid　structure　was　designed　and　the　regulation　range　of　magnetic　flux　and　voltage　was　obtained.　The　main　parameters　of　the　permanent　magnet　excitation　and　electric　excitation　generators　were　designed.　The　study　results　show　that　the　salient　pole　structure　of　electric　excitation　can　adjust　the　voltage　in　two　directions　which　we　called　Bidirectional　regulation　generator.　The　voltage　regulation　capability　of　permanent　magnet-salient　pole　hybrid　structure　in　the　forward　direction　is　much　greater　than　the　reverse　direction.　The　reference　voltage　U0　=　344 V.　When　the　rotating　speed　of　the　test　prototype　n　=　4000 rpm.　The　maximum　output　power　of　the　prototype　is　P　=　3.1 kW.　The　voltage　regulation　capability　is　±　8%.　©　2022,　The　Author(s)　under　exclusive　licence　to　The　Korean　Institute　of　Electrical　Engineers.