Fuente: WIPO "tomato" The present disclosure provides a natural porphin salt and a use thereof as a plant growth regulator and a plant immunity inducer. The porphin salt includes a salt of porphin or a salt of chlorin. Compared with the prior art, the porphin salt of the present disclosure has high stability, exhibits a stable and reliable quality during long-term storage, has a long shelf life, and is easy to carry and transport. The porphin salt has prominent water solubility, is easy to prepare into an aqueous solution with a stable content, and exhibits excellent reproducibility when applied to the field. The porphin salt can be conveniently applied at a low concentration with a strong activity and a prominent control effect. Raw materials for preparing the porphin salt are natural and widely available. The preparation of the porphin salt is emission-free, pollution-free, energy-saving, and eco-friendly.