Ancient trees is an important part of city greening, has the important scientific, historical and ornamental value. The traditional tree growth way of collecting information using artificial tape measure or difficult to operate, inefficient and cumbersome set of large-scale measuring instruments, time-consuming, laborious, accuracy is not high. The design of the tree measurement method based on image combines computer vision and mathematics geometry model, With the android intelligent terminal platform of easy to carry and operate, design tree height, diameter and crown measurement model, which avoid using cross references, and design trees information collection system, To improve the measurement accuracy of the trees, using the camera calibration technique and coordinate correction method to correct the image distortion in opencv, Orthogonal experiment analysis is a good method to analyze the optimum shooting environment and provide valuable guidance to improve the accuracy of the data. The relative error is controlled at about 4%; This method has the advantages of convenient carrying, simple operation, wide application range and high accuracy.