An automatic control apparatus for a carburetor choke valve includes a pull-rod, throttle control lever, choke block, and temperature control assembly which is arranged on a cylinder head through a bracket having a rotating shaft and coil spring. The rotating shaft is connected to the spring and one end of the pull-rod via a rotary arm. The other end of the pull-rod is located at a choke valve shaft. The block and valve shaft are connected to respective ends of the lever. During cold start, the block is opened driving the lever to pull the valve shaft. When rotated through a certain angle the valve shaft is blocked by part of the pull-rod, such that the valve and block cannot be fully opened. During warm start, the valve shaft when returning is blocked by another part of the pull-rod such that the valve cannot fully close.