The invention discloses a method for chemosynthesis of the hypericin and its derivant. The said method includes the following steps: 1) dissolving 1, 3, 8-trihydroxy-6-methyl anthraquinone in the analytical pure glacial acetic acid,then adding concentrated hydrochloric acid with 36-40 % of zinc bichloride dehydrate, reacting for 1-4 hours at the temperature of less than 125 DEG C, cooling, and obtaining the 1, 3, 8-trihydroxy-6-methyl anthranone; 2) making 1, 3, 8-trihydroxy-6-methyl anthranone, pyridine, piperidine, nitrogen-oxygen pyridine and ferrisulphas hepthydrate react free of light for 0.5-3 hours at the temperature of 100-130 DEG C, then dissolving the reaction products in the acetone, illuminating them by a halogen lamp for 12-24 hours, thickening and dissolving them in the skellysolve B, filtering the deposition, and obtaining the hypericin. The method has advantages of that its operation is simple and reasonable, its cost is cheap, its productivity is high, its actual applied value is higher, so its actual value is broad.