Aiming at the pickup of mobile phones in narrow locations such as sewers and jointing, this study proposes a method of servo mechanical arms for grabbing based on machine vision. Firstly, the camera on the eye-in-hand mechanical arm is calibrated, followed by image preprocessing and target detection. In the pose detection, we propose an algorithm to solve the pose of the mobile phones based on the two-dimensional coordinate system. It turns out that the best pose angle is only related to the difference in the pixel coordinates of the clamping point, and the size of the pose angle determines the rotation angle of the gripper. Then, the pose detection is simulated by Matlab, including target detection with SURF invariant feature points and pose calculation. Finally, the right arm of a two-armed Rethink robot grasps a mobile phone for verification. The results show that within the allowable error range, the proposed algorithm accurately guides the servo mechanical arms to grasp mobile phones.