Abstract: The study showed that Dendrolimus wensshanensis occurred two generations each year, that crossed two years in Hongta District of Yuxi Municipality. The larvae of first generation appeared in late June; then the cocoon spinning and pupation of the first generation took place in the mid-August; the prosopon emergence and oviposition happened in early September. The larvae of the second generation hatched in late September, and the second and the third instars overwintered in mid-November of the first year. The overwintered larvae started to feed and cause damage to the host plants in late February of the second year, the cocoon pinning and pupation of the second generation took place in the mid-May, and the prosopon emergence of the second generation and oviposition happened in early June of the second year. Then another life cycle started. The study showed that the best control period of time for Dendrolimus wenshanensis in Hongta District was the prosopon emergence of the first generation and before the larvae overwintering of the second generation.