In the task of 3D human pose estimation, the complex topology formed by the connection relationship between human joints presents a challenge. Effective capture of the connections between local joints is possible through modeling this structure with a graph convolutional network. Although non-adjacent joints lack direct physical connections, Transformer encoders establish contextual relationships between joints, which is crucial for better human posture inference due to the biomechanical constraints influencing human motion and pose, as well as the synergistic interaction of human joints. Balancing model performance with a reduction in the number of parameters is of particular importance for large-scale models. To tackle these challenges, a multi-layer spatial feature fusion network model (MLSFFN) based on graph convolution and Transformer is designed. This model proficiently fuses local and global spatial features with a relatively minimal parameter set. Experimental results demonstrate that the proposed method achieves a mean point per joint error (MPJPE) of 49.9 mm on the Human3.6M dataset with only 2.1M parameters. Moreover, the model demonstrates a robust generalization capability.