Heterogeneous single-atom catalysts (SACs) involve isolated metal atoms anchored to a support, displaying high catalytic activity and stability in many chemical reactions. This work reports a computational study of six carbon atom-doped (8, 0) single-walled boron nitride nanotubes (CBNTs) loading Pd atom as SACs for Heck reaction. The coordinative structure–catalytic performance relationship of the Pd1/CBNT SACs was investigated. Our simulations demonstrate that the activity of the Pd1/CBNT catalysts depends on the coordination number between the Pd center and the support as well as the local electronic environment around the Pd atom. Moreover, the difference between the Pd–C (carbon atom in a carrier) and Pd–CPh (carbon atom in chlorobenzene) bond orders could be used as a descriptor of the activity of the SACs. The Pd1/BNT-CN (the nitrogen atom of BNT was replaced with carbon atom) catalyst was found to be optimum for the Heck reaction, owing to its excellent stability and activity that was even higher than their homogeneous analogues. Thus, this study provides a method for the design and screening of SACs for both high stability and activity of the Heck reaction.