Abstract: An extensive survey was made of the adaptive character and species choice of main planting trees of farmland shelterbelt in the Pearl River Delta.On the basis of investigation and analysis,the acidity of soil,the total content of salt and the height of water level were determined as the main site factor affecting the growth of forest by means of mathematical statisties.The optimum equation was selected by regression: y_D(over pH6.1)=8.0927-0.6473x₁-0.5059x₂ y_D(under pH6.1) = 3.7641-16.6671x₁-0.0027x₂ Taxodium distichum,Taxodium ascendens,Casuarina equisetifolia,and Glyptostrobus pensilis are the main planting tree species of farmland shelterbelts in the Pearl River Delta.pH6.1 is the optimum value of soil acidity suitable to Taxodium distichum and Taxodium ascendens,and pH 7.0—8.0 suitable to Casuarina equisetifolia and Glyptostrobus pensilis.All the 4 species of trees have certain salt-resistant capability,when they are planted on the salinized soil the total salt content of which is 0.38%,they still grow well; but growing speed of Taxodium distichum and Taxodium asoendens shows negative correlation to the total salt content of soil.Water-resistant and moisture-resistant species Taxodium distichum,Taxodium asoendens,and Glyptostrobus pensilis on the planting point,i.e.50cm and 30cm above the water level,show the best performance. 5 site types are classified in the Pearl River Delta,i.e.lower downland leaching type,the plain fresh water type,the network tide-irrigating type,the seashore acid overflówing type and the seashore sandy type.Various tree species suited for planting in the farmland shelterbelt are recommended according to different site types.