A control instruction transmission method includes: after unsuccessfully occupying a first frequency-domain resource, occupying a second frequency-domain resource, wherein the first and second frequency-domain resource are different unlicensed frequency-domain resources; and starting timing from a pre-set detection moment, and when the timing duration reaches a pre-set duration, sending a control instruction by means of the second frequency-domain resource. A base station can configure different unlicensed frequency-domain resources for a terminal. After occupying a first frequency-domain resource unsuccessfully, the base station occupies a second frequency-domain resource, and starts timing from a pre-set detection moment, and when the timing duration reaches a pre-set duration, sends a control instruction through the second frequency-domain resource, thereby ensuring that when unsuccessfully occupying a certain unlicensed frequency-domain resource, the base station can also send a control instruction through occupying another unlicensed frequency-domain resource.