The invention discloses a guidance system capable of adjusting tillage line spacing. The guidance system comprises cameras, a sensor and a video processing device, wherein the cameras are arranged on the two sides of the front end of a tillage machine; the sensor is arranged above a steering shaft of a front wheel of the tillage machine; the video processing device is arranged on an operating platform in a cab; the video processing device comprises a shell, a video superposing processor, a display, a sound generator, a line spacing adjusting function button and a power switch; the video superposing processor is fixedly arranged in the shell; the display, the sound generator, the ling spacing adjusting function button and the power switch are arranged on the shell and are connected with the video superposing processor correspondingly; and a photography instrument and the sensor are connected with the video superposing processor correspondingly. The guidance system applies a video signal superposing technology to the line spacing control of a large-sized tillage agricultural machine for the first time, solves the problem about the current crop tillage ling spacing control, is easy to operate, has the advantages of high intelligentization, high accuracy degree and the like, and has good market prospect.