The utility model discloses a four-lock type car changing three compartments into two compartments, and relates to the trunk deformation technology of a common three-compartment car. The four-lock type car changing the three compartments into the two compartments comprises a car roof, a rear car window, a segmental support, a trunk, a trunk cover and a trunk side wall. The four-lock type car changing the three compartments into the two compartments is characterized in that the upper portion of the rear car window is hinged with the car roof, the lower portion of the rear car window is connected with the trunk cover through the segmental support, glass lifting mechanisms are symmetrically arranged in the trunk side wall, two sides of the inside of the trunk are symmetrically provided with crank-link mechanisms, the crank-link mechanisms are connected with the trunk cover, and motors of the crank-link mechanisms are installed in the trunk. The four-lock type car changing the three compartments into the two compartments has the advantages of being novel in design, simple and convenient to improve, low in cost, safe and reliable, good in economy, aesthetic sense, safety and comfort, and the like. Accordingly, the four-lock type car changing the three compartments into the two compartments is novel and a combination of economy and practicality.