Hypocrellin A (HA) has abundant electronic excited-state properties, and is probably used to new-style photosensitizer of photodynamic therapy, laser dye and novel photoelectron material. The transient-grating properties of hypocrellin A in solvent with different polarity and glutinosity and the solvent are studied with transient-grating technology. The ultrafast process of the transient grating results from the decay of transitional state (TS*) produced by hypocrellin A proton transfer. The lifespan of the transitional state (TS*) is 10.5 ps and is independent of polarity and glutinosity of the solvent.