The invention discloses a non-pump type organic Rankine cycle method and device for power generation. High-temperature high-pressure working medium steam which is generated by a boiler is used for pressurizing liquid working media and conveying the liquid working media, then liquid working media to be conveyed in a next cycle are pre-pressurized, and energy of the high-temperature high-pressure working medium steam is sufficiently used for improving power generation efficiency of a system. The device comprises the boiler, an expansion machine, a generator, a condenser and a liquid storing device. The liquid storing device comprises two or more liquid storing tanks which are connected in parallel and matched. Each liquid storing tank is respectively communicated with the boiler, the condenser and the other matched liquid storing tank through control valves. The boiler is sequentially connected with the expansion machine, the generator, the condenser and the liquid storing device in series to form a loop, and the steam in the expansion machine expands and does work to drive the generator to generate power. According to the device, non-pump cycle of the system is achieved, the number of moving parts is reduced, and moving performance is more stable and reliable. Energy using of the system is more economical and reasonable, thermal loads of cooling water are reduced, and net power generation efficiency is greatly improved.