Although chemoselective hydrogenation of unsaturated aldehydes is the major route to highly valuable industrially demanded unsaturated alcohols, it is still challenging, as the production of saturated aldehydes is more favorable over unsaturated alcohols from the view of thermodynamics. By combining the structural features of porous nanowires (NWs) and metal‐organic frameworks (MOFs), a unique class of porous Pt‐Ni NWs in situ encapsuled by MOFs (Pt‐Ni NWs@Ni/Fex‐MOFs) is designed to enhance the unsaturated alcohols selectivity in the cinnamaldehyde (CAL) hydrogenation. A detailed catalytic study shows that the porous Pt‐Ni NWs@Ni/Fex‐MOFs exhibit volcano‐type activity and selectivity in CAL hydrogenation as a function of Fe content. The optimized porous PtNi2.20 NWs@Ni/Fe4‐MOF is highly active and selective with 99.5% CAL conversion and 83.3% cinnamyl alcohol selectivity due to the confinement effect, appropriate thickness of MOF and its optimized electronic structure, and excellent durability with negligible activity and selectivity loss after five runs. Porous Pt‐Ni nanowires (NWs) within metal‐organic frameworks (MOFs) are successfully constructed by using organic ligands to in situ coordinate with the dissolved Ni2+ during the dealloying process. The porous Pt‐Ni NWs@Ni/Fex‐MOFs exhibit volcano‐type activity and selectivity in cinnamaldehyde hydrogenation as a function of Fe content. The optimized porous PtNi2.20 NWs@Ni/Fe4‐MOF shows 99.5% cinnamaldehyde conversion and 83.3% cinnamyl alcohol selectivity.