With high spatial but low temporal coherent nanosecond (ns) green light, ns pulsed illumination phase-contrast microscopy is successfully constructed. The pulsed illumination phase-contrast microscopy can provide ns time resolution to resolve transient dynamics of transparent targets with high contrast ratio that cannot be achieved with traditional bright-field or phase-contrast microscopies. Transient dynamics of laser-induced microcavitation is successfully recorded with this imaging technique to demonstrate its capabilities. In addition to tracing the evolutions of vapor bubbles and shockwaves during a laser-induced microcavitation, this imaging technique can sense the refractive index change of the transparent target during a pressure field variation.