The invention provides an improved optical fiber turbine flowmeter. The improved optical fiber turbine flowmeter is composed of a shell (1), a front flow guide element (2), a fore bearing (3), a rotating turbine (4), a rear bearing (5), optical fiber (6) and a rear flow guide element (7). The helix angle beta of rotating turbine blades (12) of the turbine flowmeter is designed to be 45 degrees, and the helix angle beta of front flow guide element blades (10) is designed to be 45 degrees, so that driving moment of the rotating turbine (4) is effectively increased, the starting flow rate is reduced, the range ratio is increased, and sensitivity is improved. In addition, the optical fiber (6) is sealed in rear flow guide element blades (16), an optical fiber probe end face (8) is effectively prevented from being polluted by fluid, and therefore the flowmeter can operate reliably for a long time. Flattening, silver film plating and trepanning are conducted in a 2mm region at the tail end a rotating shaft (14) to obtain a through hole (11) and a silver film plated surface (13) of the rotating shaft, different reflection rates are provided, rotating speed signals are converted into optical signals of pulse changes, and the rotating speed of the turbine is measured by measuring the reflected light impulse frequency.