The　water　gas　shift　reaction　is　an　important　procedure　in　high-purity　hydrogen　production,　and　achieving　high　CO　conversion　in　one　single　reactor　is　a　key　optimization　objective.　This　work　has　developed　a　novel　radial　flow　fixed-bed　reactor　for　water　gas　shift　reaction　with　integrated　variable　heat　exchange　and　numerically　investigated　the　system　optimization　concepts.　The　continuous　heat　removal　from　the　catalyst　bed　has　been　proven　to　fully　improve　CO　conversion　at　a　lower　H2O/CO　molar　ratio.　The　heat　transfer　rate　distribution　can　also　be　flexibly　adjusted　to　ensure　sufficiently　high　and　low　temperatures　in　the　early　and　late　stages　of　the　reaction,　respectively,　for　a　higher　conversion.　With　sufficient　coolant,　low-temperature　and　high-temperature　catalysts　for　water　gas　shift　reaction　can　be　combined　in　one　reactor　to　increase　CO　conversion　to　over　98%,　and　the　delayed　heat　removal　configuration　can　achieve　the　highest　CO　conversion　(98.50%)　with　the　least　proportion　of　low-temperature　catalysts　(9.2%).