Abstract: Location-based service (LBS) as an information sharing platform can help people obtain more useful information. But with the increasing number of users, LBS is faced with a serious problem of information overload. Using the recommender system to filter information and help users to find valuable information has become a hot research topic in recent years. In LBS, only positive implicit feedback is available and user cold-start problem in this scenario is not well studied. Based on the observations, we consider the characteristics of location-based services platform and propose a recommender algorithm, which combines collaborative PMF (probabilistic matrix factorization) with GBDT (gradient boosting decision tree), to solve the cold start problem. The algorithm first use multi probabilistic matrix factorization to learn user latent feature in different dimension, and then use gradient boosting decision tree to train the factor and label to learn the user’s preference, finally use the improved top-N recommender which considers the budget problem to produce the recommendation list. The experimental results on the real data show that the proposed algorithm can achieve better results in accuracy and F1 than other popular methods, and can solve the cold-start problem in LBS recommendation.