The invention discloses a four-connecting bar type extending leveling control system. The four-connecting bar type extending leveling control system comprises a working platform, four suits of landing legs and four suits of support legs, each suit of support legs is connected with the working platform through two extending arms and one suit of landing legs, the landing legs, the support legs and the working platform make up a parallel four-connecting bar mechanism, a horizontal sensor, a proximity switch and a control box are arranged on the top of the working platform, a PLC controller connected with the horizontal sensor and the proximity switch is arranged in the control box, the control box is provided with a display output device and an RS-485 communication cable connected with the PLC controller, the PLC controller controls the extending and retracting of each of the landing legs and the support legs through the proximity switch and the horizontal sensor, and the horizontal precision of the horizontal sensor in the XY direction is displayed in the display output device. According to the four-connecting bar type extending leveling control system, each support leg is provided with one landing leg, the support leg is capable of extending and retracting independently, so that the support leg can be protected effectively, and moreover, the equipment upsetting moment is increased, and the equipment working stability is improved.