CshA is a dimeric DEAD-box helicase that cooperates with ribonucleases for mRNA turnover. Here, we report the crystal structure and small-angle X-ray scattering solution structure of the CshA from Geobacillus stearothermophilus. CshA is exclusively a dimeric protein with the RecA-like domains of each protomer forming a V-shaped structure. CshA binds RNA with or without ATP/ADP, as RNA remain bound with CshA during ATP hydrolysis cycles. RNA is thus degraded processively through cooperation between exoribonucleases and CshA in the RNA-degrading machinery.