Venus exploration is the key to answering the formation and evolution of terrestrial planets in the solar system, exploring the formation and future of habitability of Earth, and developing a search strategy for habitable planets in the exoplanets. Due to the harsh environmental conditions on Venus, multiple challenges to technology, and high costs, exploration and scientific study of Venus lags far behind that of the Moon and Mars. Here, we summarize the research progress, critical scientific questions, and technological requirements of Venus exploration and propose objectives and structure element types for future Venus missions. At present, most advances have been made in the study of the atmosphere and climate of Venus, including atmospheric structure and chemistry, energy balance and thermal structure, clouds and haze, atmospheric circulation and dynamics, and climate evolution. There have also been significant advances in the physical chemistry of the upper atmosphere and the interaction of the solar wind with Venus. In contrast, research of the surface and interior of Venus is relatively lagging. Present studies have investigated the topographic characteristics of Venus' surface, the history of impact and resurface, volcanoes and tectonic activities, the composition of surface materials, and the interaction between the surface and the atmosphere. Due to limited spatial coverage and data resolution, many major scientific questions are left unanswered. Besides Venus missions, ground- based observations, laboratory simulations, and numerical simulations are crucial for Venus study. Simulation facilities are essential in supporting mission developments and scientific research. The next decade is crucial for China to consider the Venus exploration mission and a critical period for developing related technologies. This review is intended for Chinese scientists and engineers interested in the science and exploration of Venus, planetary science, and solar system exploration.