The invention discloses a Ganoderma lucidum karst cultivation method for improving ganoderma lucidum polysaccharides and selenium content. The method comprises the steps of 1, preparation of a culture medium, wherein the culture medium is prepared from, by weight, 75 parts of sawdust, 20 parts of wheat bran, 2 parts of corn flour, 1 part of lime, 1 part of gypsum and 1 part of sugar, and the ratio of the materials to water is adjusted to 1:(1.3-1.5) with a selenium-rich nutrient solution; 2, material mixing, bagging, sterilization and inoculation; 3, spawn running, wherein the inoculated culture medium is placed in a greenhouse for spawn running, at the beginning, the greenhouse temperature is controlled to be 26-28 DEG C, at the 20th day after inoculation, the greenhouse temperature is increased to be 34 DEG C and kept for 20-24 h, and then recovered to be 26-28 DEG C; 4, ganoderma lucidum karst germination, wherein after hyphae grow to be filled with the bag, ganoderma lucidum karst enters into a ganoderma lucidum karst germination period, and the greenhouse temperature is increased to be 34 DEG C at the 5th day, the 10th day, the 15th day and the 20th day in the ganoderma lucidum karst germination period respectively, kept for 20-24 h and then recovered to be 26-28 DEG C.