Abstract: This paper aims to make an objective and quantitative assessment of the economic benefits of meteorological forecasts in serving agro-ecology. The author built an information-state matrix, and provided the general mathematical formulae for the probability sets of the product- events of information- state probabilities. The result showed that the general methods were applicable to such an assessment. The authors described the basic principles on the concept of meteorological yields. Those practical observation data in Kazuo of 1999-2013 were taken as information resource to forecast fresh gale and serve sun-light greenhouses in Kazuo, and the authors obtained the following computed results: (1) the total economic benefit in Kazuo was 6304×104 yuan/a; (2) the benefit-cost ratio was 65.6:1. From the above research, the author drew conclusion that both principles and methods mentioned above might be applied to the relevant fields of evaluations on meteorological- ecology economic benefits.