Event cameras detect intensity changes rather than absolute intensity, recording variations as a stream of “event.” Intensity reconstruction from these sparse events remains a significant challenge. Previous approaches focused on transforming motion-induced events into videos or achieving intensity imaging for static scenes through modulation devices at the acquisition end. In this paper, we present inter-event interval microscopy (IEIM), a paradigm-shifting technique enabling static and dynamic fluorescence imaging through photon flux-to-temporal encoding, which integrates a pulse-light modulation device into a microscope equipped with an event camera. We also develop the inter-event interval (IEI) reconstruction algorithm for IEIM, which quantifies time intervals between consecutive events at each pixel. With a fixed threshold in the event camera, this time interval can directly encode intensity. The integration of pulse modulation enables IEIM to achieve static and dynamic fluorescence imaging with a fixed event camera. We evaluate the state-of-the-art performance of IEIM using simulated and real-world data under both static and dynamic scenes. We also demonstrate that IEIM achieves high-dynamic, high-speed imaging at 800 Hz in mimetic dynamic mice brain tissues. Furthermore, we show that IEIM enables imaging the movements of in vivo freshwater euglenae at 500 Hz.