Today, management of knowledge is a Effective and powerful tool for achieving competitive advantages and is regarded as a method for supervision and guidance of tangible and particularly intangible knowledge assets of organizations. On the other hand, extent of employees' intelligence and mind in constructive and effective application of knowledge for achieving individual and organization objectives reveals their qualitative differences. Spiritual intelligence due to its link to meaning, value and nurture of imagination empowers employees to effect change and development in organization. Hence, given importance of spiritual intelligence and management of knowledge in organizations, present research investigates effect of spiritual intelligence on effectiveness of knowledge management Practices in Department of Financial Supervision and Treasury General of Ministry of Economic Affairs and Fianace.To assess effectiveness of knowledge management Practices, Marquis & Simon Model Standard Questionnaire (2006) and to investigate constituents of spiritual intelligence, Heldbrent Standard (2011) which is based on King Model (2008) is used. For data analysis, Kolmogorov-Smirnov Tests, correlation coefficient, one-sample t-test, linear regression, and Friedman Ranking Test were used as statistical methods.The findings suggest that spiritual intelligence has significant effect on effectiveness of knowledge management Practices. In other words, by development of employees' spiritual intelligence, effectiveness of such Practices as tendency towards development, knowledge transfer and support, Continuous learning in organizations, Understanding the organization as a global system, Develop an innovative culture that supports research and development projects will, Approaches based on individuals and Competency development and management based on competency will significantly increase in organization and by profiting from the achieved results, in a new world which constantly is in change, organizations will be able to surpass their competitors.