A method of producing and purifying β-carotene by Blakeslea trispora fermentation, comprising the following steps: a) separately inoculating strains of Blakeslea trispora "+" and "-" onto a PDA culture medium, culturing at 25-30°C for 48-60 hours, and then eluting spores to a spore suspension by a sterile saline after growth of a great deal of spores; b) culturing and propagating spores of the fresh spore suspension in a seeding tank at pH=6.3-6.8 and the cultivation temperature of 25-30 °C to seeds for fermentation, wherein the seed medium comprises corn starch, dextrose, vegetable oil, thiamine hydrochloride, magnesium sulfate and emulsifier; c) inoculating the seeds for fermentation in the seeding tank of step b) onto a fermenter and then fermenting so as to produce a fermentation liquid at pH=6.5∼6.8 and the cultivation temperature of 27-30°C; wherein the medium is high-speed sheared and emulsified by a colloidal mill before inoculating, the medium of the fermenter comprises corn starch, corn syrup, meal bread flour, vegetable oil, dipotassium hydrogen phosphate, magnesium sulfate, thiamine hydrochloride, and/or emulsifier; d) adjusting the fermentation liquid of step c) to be pH=8.0∼8.5 by using an organic or inorganic base, and then filtrating so as to obtain wet mycelia; e) treating the wet mycelia of step d) with hydrophobic non-polar organic solvent at 0°C∼60°C, extracting and continuously filtering so as to obtain a wet mycelia without fat-soluble impurities; f) mixing the wet mycelia of step e) with an organic solvent of esters at the temperature from 10°C to a boiling point of the solvent, and then concentrating to dryness in vacuum at the temperature≤ 40 °C to obtain a concentrated solution; and g) adding a C1∼C6 saturated monohydric alcohol to the concentrated solution at 10°C∼80°C, filtering and crystallizing so as to obtain pure β-carotene. a) separately inoculating strains of Blakeslea trispora "+" and "-" onto a PDA culture medium, culturing at 25-30°C for 48-60 hours, and then eluting spores to a spore suspension by a sterile saline after growth of a great deal of spores; b) culturing and propagating spores of the fresh spore suspension in a seeding tank at pH=6.3-6.8 and the cultivation temperature of 25-30 °C to seeds for fermentation, wherein the seed medium comprises corn starch, dextrose, vegetable oil, thiamine hydrochloride, magnesium sulfate and emulsifier; c) inoculating the seeds for fermentation in the seeding tank of step b) onto a fermenter and then fermenting so as to produce a fermentation liquid at pH=6.5∼6.8 and the cultivation temperature of 27-30°C; wherein the medium is high-speed sheared and emulsified by a colloidal mill before inoculating, the medium of the fermenter comprises corn starch, corn syrup, meal bread flour, vegetable oil, dipotassium hydrogen phosphate, magnesium sulfate, thiamine hydrochloride, and/or emulsifier; d) adjusting the fermentation liquid of step c) to be pH=8.0∼8.5 by using an organic or inorganic base, and then filtrating so as to obtain wet mycelia; e) treating the wet mycelia of step d) with hydrophobic non-polar organic solvent at 0°C∼60°C, extracting and continuously filtering so as to obtain a wet mycelia without fat-soluble impurities; f) mixing the wet mycelia of step e) with an organic solvent of esters at the temperature from 10°C to a boiling point of the solvent, and then concentrating to dryness in vacuum at the temperature≤ 40 °C to obtain a concentrated solution; and g) adding a C1∼C6 saturated monohydric alcohol to the concentrated solution at 10°C∼80°C, filtering and crystallizing so as to obtain pure β-carotene.