A new broadband ground coplanar waveguide (GCPW) transition is proposed for three dimensional back-to-back transition of GCPW. Firstly, we need to research GCPW-to-CPW transition and then using gold belt bonding to realize the transition of three dimensions CPW. As design examples, the fabricated transitions in back-to-back configuration provide insertion loss less than 0.5 dB per transition and return loss better than 16.7 dB for frequencies form 2 GHz to over 17.5 GHz. This method effectively solved the problem of back-to-back GCPW transition and has the advantages of simple structure, small size and easy to realize in project.