The　controlling　of　anisotropic　structure　in　smart　hydrogels　is　essential　to　fabricate　hydrogel-based　soft　actuators.　Herein,　a　facile　strategy　to　fabricate　smart　hydrogel　with　controllable　anisotropic　structure　and　the　corresponding　deformability　is　proposed.　Poly(N-isopropylacrylamide)　(PNIPAM)　hydrogel　is　fabricated　as　actuator　by　asymmetric　growth　of　silver　(Ag)　microdendrite　structures　in　the　hydrogel　matrix　through　a　phototriggered　electroreduction.　The　existence　of　Ag　microdendrite　structures　at　specific　area　in　hydrogel　changes　the　swelling/shrinking　rates　of　the　related　region,　which　driving　the　deformation　behavior　of　the　hydrogel.　By　adjusting　the　electroreduction　parameters　and　the　patterns　on　the　reducing　electrode,　distribution　of　Ag　microstructures　both　along　the　vertical　and　lateral　direction　in　hydrogel　matrix　can　be　precisely　controlled,　which　further　enables　designed　deformations　of　the　hydrogel　nanocomposites.　As　a　result,　various　soft　actuators　such　as　bending　beam,　gripper,　and　flower-shaped　actuator　are　designed,　and　the　temperature　triggered　actions　of　these　actuators,　such　as　curling　and　gripping　are　realized.　©　2021　Wiley-VCH　GmbH