Considering the high complexity of traditional camera calibration process and the low accuracy of three-dimensional measurement we proposed a kind of binocular visual 3D measurement method based on projection line and a calibration method based on Neural Network.According to the characteristics of camera imaging the projection straight line equation was calculated by two points on the calibration plane.To the complex distorted model of camera imaging the powerful ability of BP neural network for fitting the complicated nonlinear mapping relation was used for left and right cameras implicit calibration at the far and near distance calibration planes and mapping relationship between two-dimensional physical coordinates of plane template and pixel coordinates of image was obtained.A test platform was designed and established, and grid template training samples were obtained by using the manual assisted method.This calibration method is fully applicable to the large field-of-view close range high-precision binocular vision sensor.Test results show that the measuring error of known length in the space is about 0.109 mm and the system has a high measuring accuracy.