Multi-ring perfect vortex beams enable the multi-parameter detection of rotating objects, providing distinct advantages in various applications. Generating fine rings is essential in improving signal-to-noise ratio for microscopic detection. However, the current method of directly modulating with spatial light modulators is hindered by pixelization. Here, we proposed an approach based on the Bessel beam kinoform and cross-polarization superposition to generate high-quality beams with fine ring radius. Through simulations and experiments, we demonstrate its advantages in enhancing the signal-to-noise ratio and measuring velocity gradient. This approach provides a universal strategy for beam design and velocity gradient detection in fluidic environments.