In order to solve the problem that detection algorithm of unmanned aerial vehicle (UAV) can not detect UAV quickly and accurately, an improved real-time lightweight UAV detection algorithm based on SSD is proposed, which is called TSSD. Firstly, a lightweight backbone network is improved to solve the problem of large amount of weights parameters in the backbone network of SSD algorithm. Secondly, SSD only uses multi-layer feature map for multi-scale prediction, but the relationship between features is not well utilized, and a feature enhancement module is added to improve the detection ability. The experimental results of the self-built UAV dataset show that the detection speed of the proposed algorithm is 125f/s, which is much higher than that of the original SSD, and the accuracy of the proposed algorithm is also higher than that of the latter.