A control structure is provided for a throttle valve of engine. The throttle valve includes a throttle plate arranged inside the valve body and mounted to a control shaft having an end extending outside the valve body and received in a control seat mounted outside the valve body and having a shaft hole seat, a constraint block, a coupling hole seat, and a cable outlet section. A control assembly includes a return spring and a control rocker arm that includes a connection section forming a connection hole to be fit over the control shaft and a cable connection section, a positioning section, and a push section. The control motor is mounted to the coupling hole seat of the control seat and has a driving rod having a front tip section positioned against the push section of the control rocker arm. The control seat lid is secured to the control seat.