Grouted Bellows Connect Rebar (GBR) technology is critical for ensuring reliable connections in precast concrete components. The bond-slip behaviour, a core metric for assessing GBR connection performance, presents significant complexity, and existing empirical models often fall short in prediction accuracy to meet engineering demands. Addressing this challenge, this study introduces an innovative hybrid model (CNN-LSTM) that integrates convolutional neural networks with long short-term memory networks. Utilizing eight critical parameters, such as grouting strength, reinforcement ultimate strength, and the anchorage length-to-diameter ratio of the reinforcement, the model achieves precise predictions of GBR bond stress. This study systematically collected data from 114 sets of GBR pull-out tests, constructing a dataset comprising 2,272 bond-slip samples for model training and validation. Additionally, 15 GBR independent samples were independently fabricated and multiple samples were extracted to assess the model generalization capability. Experimental results demonstrate that the CNN-LSTM model significantly outperforms traditional empirical models in predicting bond stress and exhibits superior generalization across key metrics, including total energy consumption, maximum bond stress, failure modulus, and residual energy. Parameter importance analysis reveals that grouting strength, reinforcement ultimate strength, and the anchorage length-to-diameter ratio are the most influential factors in bond stress prediction. Building on the CNN-LSTM model predictions, this study establishes an improved empirical model with clear physical significance, offering a reliable computational foundation for engineering applications.