The invention provides a yeast strain capable of excessively synthesizing extracellular cAMP, a constructing method and a fermentation technology thereof, and an application of the yeast strain in the fields of medicines, livestock husbandry, foods, health foods or chemical industry. The yeast strain comprises first gene modification and second gene modification, wherein the first genes are protein kinase A (PKA) catalytic subunit coding genes TPK1, TPK2 and TPK3, the first genes are modified to completely inhibit the activity or expression of the PKA in order to eliminate the feedback inhibition of cyclic adenosine monophosphate (cAMP) and inhibit the growth of yeast, and the second gene modification eliminates the first gene modification induced growth inhibition in order to make yeast grow normally and increase the cAMP yield of the yeast. The yeast strain further includes third gene modification, fourth gene modification, and / or fifth gene modification. The recombinant yeast strain can stably, continuously and highly-efficiently produce the extracellular cAMP.