In order to address the low accuracy and speed of detection by manual and traditional automation methods for the weld seam surface of traction seat， a lightweight weld seam quality detection algorithm YOLOv5s-G2CW was proposed for the weld seam surface of traction seat. Firstly， the GhostBottleneckV2 module was applied as a replacement for the C3 module in YOLOv5s to reduce the number of parameters used in the model. Then， the CBAM （Convolutional Block Attention Module） was introduced into the Neck of the YOLOv5s model for integration of the weld features in two dimensions： channel and space. Also， the positioning loss function of the YOLOv5s model was improved into Wise-IoU， focusing on the predictive regression of ordinary quality anchor frames. Finally， the \mathrm{13} \times \mathrm{13} feature layer used for the detection of large-sized objects in the YOLOv5s model was removed to further reduce the number of parameters used in the model. Experimental results show that， compared with the YOLOv5s model， the size of YOLOv5s-G2CW model reduces by 53.9%， the number of frames transmitted per second increases by 8.0%， and the mAP （mean Average Precision） value increases by 0.8 percentage points. It can be seen that the model is applicable to meet the requirements for real-time and accurate detection of the weld seam surface for traction seat.