A pretreatment particle-accelerating deposition and separation apparatus and method for purifying turbid raw water, which based on the theories of laminar flow requirement, particle-accelerating vertical deposition and water horizontal movement, separates water molecules from turbidity particles in a laminar flow region (with a Reynolds number lower than 1,000). By accelerating the velocity of high-turbidity raw water and the turbidity particles, the particles settle vertically because of inertia. Thus, the turbidity particles can be removed physically from the raw water and clean water can be collected at different heights of the apparatus while concentrated turbid water can be released to a nearby body of water after appropriate treatments. Thereby, turbid water can be purified for the subsequent coagulation, sedimentation and filtration processes in traditional water treatment plants.