The certification scheme for best company has been implementing in order to stimulate the investment of private consulting company to reduce GHG emission. This study was conducted to set up the certification scheme, to suggest process, criterion, institute, committee which are necessary for the evaluation of certificate. Evaluation process for the introduction of the certification scheme is divided into 7 successive phases, (1) Certificate application(Applicant ${ ightarrow}$ Certification Institute), (2) Evaluation request(Certification Institute ${ ightarrow}$ Evaluation Institute), (3) Accept and document review(Evaluation Institute), (4) Site and document evaluation(Evaluation Institute ${ ightarrow}$ Evaluation committee), (5) Sending evaluation result(Evaluation Institute ${ ightarrow}$ Certification Institute), (6) Certification confirmation (Certification Institute), (7) Issue of certificate(Certification Institute ${ ightarrow}$ Applicant).