Multifunctional　hydrogels　have　important　applications　in　various　fields　such　as　artificial　muscles,　wearable　devices,　soft　robotics,　and　tissue　engineering,　especially　for　those　with　favorable　mechanical　properties,　good　low-temperature　resistance,　and　stimuli-responsive　capabilities.　In　the　current　study,　a　type　of　polyacrylamide/sodium　alginate/carbon　nanotube　(PAAm/SA/CNT)　double-network　(DN)　hydrogel　was　fabricated,　which　exhibited　a　high　tensile　strength　of　271.68　+/-　6.04　kPa,　a　favorable　conductivity　of　1.38　+/-　0.17　S.m(-1),　and　a　good　self-healing　ability　under　heating　conditions.　In　addition,　the　composite　hydrogel　exhibited　controllable　photomechanical　deformations　under　near-infrared　irradiation,　such　as　bending,　swelling,　swimming,　and　object　grasping.　To　further　broaden　the　applications　of　the　hydrogel　in　low-temperature　environments,　calcium　chloride　(CaCl2)　was　introduced　into　such　a　PAAm/SA/CNT　DN　hydrogel　as　an　additive.　Interestingly,　the　tensile/compressive　strengths　as　well　as　elasticity　were　well-maintained　at　a　temperature　as　low　as　-20　degrees　C.　In　addition,　the　PAAm/SA/CNT/CaCl　2　hydrogel　presented　excellent　conductivity,　recoverability,　and　strain-sensing　capability　under　such　extreme　conditions.　Overall,　the　investigations　conducted　in　this　paper　have　provided　potentially　new　methods　and　inspirations　for　the　generation　of　multifunctional　PAAm/SA/CNT/CaCl2　hybrid　DN　hydrogels　toward　extended　applications.