The invention discloses a cross breeding method capable of increasing the fruiting rate of castanopsis hystrix. The cross breeding method comprises the following steps: S1, a female parent is subjected to castration and bagging; S2, when male flowers of a male parent are in the transitional period from an initial flowering period to a full-bloom period, male inflorescence of the male parent is collected and dried; S3, artificial pollination is performed: when stigmas of female flowers of the female parent are rolled reversely at the angle ranging from 40 degrees to 50 degrees, bags are removed on a sunny day, dry male flower pollen is sufficiently scattered on the stigmas of the female flowers from 9:00 to 10:30, and then bagging is performed; S4, the stigmas of the female flowers do not have mucus or get black 3-5 days after pollination, the bags are removed, the female flowers are exposed and grow naturally, and cross-bred seeds are obtained when green cones turn brown. With the adoption of the castanopsis hystrix cross breeding method, the fruit setting rate of castanopsis hystrix can be remarkably increased, the seed quality can be remarkably improved, the pollination success rate and the fruiting rate of castanopsis hystrix are increased efficiently, and besides, the method is simple to operate, easy to control and stable in effect. The cross breeding method has great significance in solving of the problem about lack of certified seeds of castanopsis hystrix.