The invention discloses a flow velocity measurement device based on pressure induction and an implementation method thereof. A first piston (1) and a second piston (2) capable of leftward and rightward moving are installed at the two ends of the internal part of a hollow measurement cylinder (3). A sealed structure is formed between the first piston (1) and the second piston (2) and the measurement cylinder (3). A separating plate (4) is arranged in the exact middle of the internal part of the measurement cylinder (3). A U-shaped tube (5) having scales is installed on the upper end of the measurement cylinder (3). A segment of liquid column (6) is arranged in the exact middle of the internal part of the U-shaped tube (5). A handle (7) is installed on the U-shaped tube (5), and the handle (7) is arranged exactly above the measurement cylinder (3). The disadvantages that full range universality cannot be realized in the prior art can be overcome so that the flow velocity measurement device has the advantages of being simple in device principle, easy and convenient, rapid and visual in actual operation and low in cost without power driving.