The invention relates to a queue length distribution estimation method based on sampling trajectory data. The method comprises the following steps: 1) the trajectory data of sample vehicles are acquired, and the queue position information of each sample vehicle in the queue is extracted; 2) the queue position distribution of the sample vehicles in the queue is fit and obtained by adopting a kerneldensity estimation method; and 3) based on the queue position distribution of the sample vehicles, the queue length distribution in the time period is estimated and obtained. Compared with the priorart, the method of the invention has the advantages of low permeability requirements, high estimation accuracy, wide application range and the like.