The phosphorus content of apple tree canopy is estimated by using a hyperspectral remote sensing technology. Firstly, a Field Spec 3 type field spectrometer from ASD company is used to measure the hyperspectral reflectance of apple tree canopy in the shoot growth stopping period in spring. The measured spectral data are processed in a variety of transformation forms. Then, correlation of the data with the phosphorus content is analyzed. The spectral parameters more remarkably correlated with the phosphorus content are found. A phosphorus content estimation model is established after the regression analysis is made. The result shows that the near infrared band is the sensitive band of the phosphorus content of apple tree canopy. The wavelengths of 808 nm, 921 nm, 1195 nm and 1272 nm and the normalized infrared spectral index combined by these wavelengths are highly correlated with the phosphorus content of apple tree canopy. This is verified in the established estimation model. This research not only realizes the fast estimation of phosphorus content of apple tree canopy, but also provides the theoretical basis for the real-time diagnosis of nutrition of apple trees.