Recently, NMS-free detector has become a research hotspot to eliminate negative influences, while NMS-based detector mis-suppress objects in crowd scene. However, NMS-free may face the problem of sample imbalance that affects convergence. In this paper, Gaussian distribution is adopted to fit the distribution of the targets so that samples can be chosen according to it. And we propose Gaussian Balance Sampling strategy to balance positive and negative samples actively. Besides, a simple loss function, PDLoss, is proposed to eliminate duplicated matches on the label assignment procedure and increase training speed. In addition, by a novel Non-target Response Suppression method, the designed network can focus more on hard samples and improve model performance. With these techniques, the model achieved a competitive performance on the CrowdHuman dataset.