Precipitation is a climatic elements that have temporal - spatial distribution. In this research database of Global Precipitation Climatology Centre (GPCC) with a resolution 0.5×0.5 degree for 50 year is used, that was constituted with dimensions of 12800*600. Temporal data are on the columns and pixels (spatial data) located on the rows. The results show an increasing trend in spring and fall but in summer and winter precipitation trend has been decreased. The most amount of precipitation is located in the northern parts of the Black Sea and Mediterranean Sea, Southeast Asia, southern coast of the Caspian and Central Zagros Mountains. Most of Middle East (about %95) have not trend and only in some parts of Kazakhstan, Afghanistan, Pakistan ,central Iran, and areas in lower-latitude have positive trend and some East and northwest parts of Iran and some parts of Middle East also have decreasing trend of precipitation. The highest percent of area of precipitation trend gradient is 0 to 0.5.
 

 Water is a strategic and rare resource that has been severely limited in recent years due to various national and transnational variables and has severely affected the areas of security, stability, development and prosperity in countries. The high impact of water in the aforementioned areas has placed water at the center of foreign policy and hydropolitical relations of many countries, including South West Asia. In recent years, despite the issue of the water crisis and its role in the relations between Iran and Iraq in scientific, political and media circles, the dimensions of this issue remain unknown and different interpretations have been given. The current research, which is of a research nature and the required inputs were collected in a library method with the aim of obtaining a qualitative understanding of the dimensions and angles of the hydropolitical relations between Iran and Iraq, is based on the fact that, in addition to identifying the content and methodological features, the research gaps To identify the existing in this field with qualitative meta-analysis method. Using the qualitative meta-analysis method, this research has examined 34 researches conducted in the period of 2014-1402 in the form of domestic scientific-research articles, dissertations and articles in prestigious international journals. The results of the research showed that a comprehensive study has not been conducted that has investigated and analyzed the various dimensions of the hydropolitical relations between Iran and Iraq. In this regard, the lack of accurate and real data and the weakness of the theoretical-cognitive foundations of the research are among the shortcomings of the research conducted in the field of relations between the two countries.