The invention provides a method and a device for visually detecting pins of a multi-pin element. The method is based on an image processing technology. The device comprises cameras and light sources in three different directions, a cylinder clamping device, a screw rod-motor linear motion device and a laser position sensor. Through an image acquisition device formed by the backlight sources and the cameras in the three directions, in cooperation with the screw rod-motor linear motion device, the pins of the element are detected. The cameras and the light sources in the two directions acquire projected images of the pins for analysis and judge whether the pins incline or not, and the two cameras acquire the images from different directions so as to ensure that the inclination of each pin in any direction can be detected; the third camera acquires the projected images of the pins from the non-coincidence direction of the pins for analysis and detects whether each pin is broken or not. The method and the device provided by the invention can efficiently detect the pins of the multi-pin element and are suitable for high-speed and high-precision automatic optical inspection in the plug-in technology industry.