Capillary evaporation in pores is a common phenomenon in nature, and due to its high capillary pressure, low superheat and working temperature, it has a wide range of applications in high heat dissipation flux, such as porous wicks in heat pipes. Recently, a new ultra-high flux heat sink based on capillary evaporation on nanoporous membrane was experimentally studied, which can dissipate heat fluxes of 665 W/cm². However, due to challenges in experiments, the nanoscale view of capillary evaporation beside the meniscus is lacking. Here, through molecular dynamics simulations, we perform the process of capillary evaporation on nanoporous membrane with pore diameter of 8.7 nm. During this simulation, working liquid is fast and continuously conveyed from the pool to the pores by capillary force, then it absorbs heat and evaporates beside the meniscus, getting heat dissipation fluxes of 1.82±0.06×10⁴ W/cm² and heat transfer coefficients of 726±26 W/(cm²·K). Then we investigate the effect of pores surface properties, find that low hydrophilicity leads to the heat transfer deterioration, and the heat transfer coefficient relates to adsorb layers. Our study provides fundamental insight into the improvement of heat and mass transfer capability of evaporation in nanoporous of membrane, wicks and other capillary evaporators.