Abstract: The interrupted microchannel heat sink with spoilers in transverse zones is a novel structure.It consists of a set of separated zones adjoining parallel microchannels and transverse microchambers with spoilers.The heat transfer enhancement depends strongly on the disturbed effect by the spoilers in transverse zones.The structural parameters, including the lengths and widths of the rectangular microchannel regions and the spoilers have an important influence on the behavior of fluid flow and heat transfer in the microchannel with spoilers in transverse zones.This paper reports an investigation of the influence of structural parameters with three-dimensional numerical simulation over the whole heat sink.The steady, laminar flow and heat transfer equations were solved by the finite-volume method.The analysis shows that when the lengths of inlet and outlet zones both are 5 mm and the heat transfer length is 10 mm, the optimized structural parameters are L₁/L₂=4.187 5, L₂=0.4 mm, W₁=W₂=0.35 mm, and 0.5<H₂/H₁<1.