This paper presents a novel tracking-by-detection approach for multitarget tracking. There are two major steps in our framework: data association to form global tracklet association, followed by trajectory estimation to deal with the remaining gaps. In the first step, we formulate tracklet association as an inference problem in a Hough forest random field, which combines Hough forest and conditional random field and allows us to model both local and global tracklet relationships in one unified model. In the second step, we improve the reversible-jump Markov chain Monte Carlo particle filtering method with explicit mutual-occlusion reasoning to fill in the remaining gaps from the first step and increase the overall tracking precision. Extensive experiments have been conducted on five public data sets, and the performance is comparable to that of the state-of-the-art method, if not better.