The ever-dwindling freshwater sources and ever-increasing need for freshwater resources are regarded as two important concerns for current society. Solar vapor generation has proven to be an effective and reliable solar-driven technology to overcome these concerns. However, it is a big challenge to prepare low-cost and high-efficiency solar absorber for solar vapor generation. Herein, we report a novel structurally integrated solar absorber composed of CuS nanoflowers and semipermeable collodion membrane (SCM). Three-dimensional (3D) covellite CuS nanoflowers composed of nanosheets have been synthesized with a facile hydrothermal route and their morphology and structure are investigated with various analytical techniques. High solar vapor generation efficiencies of 68.6% and 81.2% were achieved with CuS/SCM under 1 and 4 sun irradiation, respectively, much higher than that of the CuS nanofluid. A stable solar vapor generation performance has been demonstrated over 20 cycles. These results display a promising potential of CuS/SCM as a solar-absorber for efficient solar vapor generation.