Disclosed are a salt of a benzopiperidine derivative and a crystal form thereof, and a method for preparing the salt and the crystal form thereof. Specifically, disclosed are an L-lysinate of (E)-3-(4-((1R, 3R)-2-(4-cyclopropyl phenyl)-6-(1-ethyl-1H-pyrazole-4-yl)-3-methyl-1, 2, 3, 4-tetrahydroisoquinoline-1-yl)phenyl)acrylic acid, a I crystal form thereof, and a preparation method therefor. The compound represented by formula (I) and the I crystal form thereof have good stabilization, has a simple process easy to operate, and can be better used in clinical treatment.