Information technology (IT) plays an obviously important role in gaining opportunities and taking the competitiveness advantages, and information strategy planning (ISP) becomes the major concern for the effective implementation of information system (IS) among researchers and practitioners. Most companies have difficulties in developing ISP due to its complexity and diversity. Thus, numerous studies have been done on ISP and the methodology for its effective devising process. However, traditional methodologies do not reflect the rapid change of IT markets and business environments. We identify the critical factor for ISP methodology, and develop the new methodology, so-called information strategy planning methodology (ISPM). Also, based on ISPM an evaluation system of ISP is proposed to enhance the quality and practicality of ISP. The evaluation system is composed of two domains, evaluation of ISP procedure and evaluation of ISP supporting systems. The evaluation system is applied to seventeen major Korean companies' ISPs to reveal its value.