Abstract: Based on the investigation of the biomass,productivity,and production structure of poplar in the farmland shelterbelt forest,the growth relationship of Populus to-mentosa and Populus daquansis has been established. The results of analysis were as follows: The biomass was 26.09 t/ha, net biotic productivity, 2.609 t/ha · a, net increased output value, 109.38 yuan/ha · a. The yield structure varied greatly depending on the situations of different trees in the shelterbelt. The relative growth equation of the two kinds of poplar, W= aDb, was fit at close correlation and high precision. It could be used to estimate the biomass of the tress in the farmland shelterbelt forest where poplar was dominant at present.