A spatial phase unwrapping algorithm based on multi-anchors bidirectional location and suppression (SPUA-MBLS) is proposed. Spatial phase unwrapping algorithms (SPUAs) can play an important role in three-dimensional (3-D) measurement due to their phase unwrapping without any additional auxiliary pattern. SPUAs based on line scanning can achieve much faster phase unwrapping line-by-line than the traditional SPUA based on reliability sort, such as the quality-guided SPUA. But they are prone to suffer from residual error propagation caused by noise. The proposed algorithm first binarizes the wrapped phase to generate a crude fringe order map with multi-anchors and then cross-validates this map forward-backward to locate and suppress those multi-anchors as much as possible. Thus, a more perfect fringe order map can be segmented to achieve spatial phase unwrapping with a more effective improvement of residual error propagation. The experimental results show the feasibility and validity of the proposed algorithm. The proposed algorithm is proved to have higher measurement accuracy, and it has also shown higher robustness in anti-noise performance while inheriting the high-speed phase unwrapping feature.