Kinship verification aims to infer whether there is a kin relation between different individuals from facial images. However, popular kinship datasets are often small and suffer from data imbalance. Most existing methods build complex networks to extract features but ignore some implicit information, like family information. They use balanced datasets with fixed negative samples for training, which overlooks valuable information from multiple negative samples, leading to poor performance and robustness. To address these issues, we propose a novel end-to-end framework for kinship verification called Online Re-weighting Relation Network (OR2Net) based on an online re-weighting strategy of meta-learning and relation network. Our novel relation network aims to extract fine-grained features and reduce differences between generations by using multi-scale features and mining family information from kinship datasets. Additionally, we design a lightweight meta re-weighting network that uses a small, clean meta-set to guide the adaptive weighing of training examples. This is done using one-step stochastic gradient descent (SGD) based on an online re-weighting strategy from meta-learning. This helps find effective hard negative samples and reduces the imbalance problem. Extensive experiments on three public kinship verification datasets show that our proposed method is more effective compared to state-of-the-art methods. The code is publicly available on https://github.com/XinZhao-dlnu/OR2N.