The complete mitochondrial genome of an orb-weaver spider Cyclosa argenteoalba is determined in this article. The genome encodes the same 37 genes with a length of 14,575 bp as all other metazoan mitogenomes. The A + T content of the majority strand is 73.1%. Among the protein-coding genes, one gene (COI) begins with TTA, three (COII, COIII and ND6) start with ATT, three (ATP6, ND3 and ND4) begin with ATA and other six genes use ATT as initiation codon. All the protein-coding genes end with the canonical termination codons (TAA or TAG), except for ND3 and ND4L, which use an incomplete stop codon (T). Thirteen transfer RNAs genes lack the potential to form the cloverleaf-shaped secondary structure. The A + T-rich region is 1052 bp in length with an A + T content of 68.9%. In the phylogenetic analyses, C. argenteoalba was nested within Araneidae and the species from the superfamily Araneoidea form a momophyletic group.