This paper makes a brief description of the two developing stages that the National gravity reference system has experienced; the system of 1957 and that of 1958. It analyses the respective precision and main technical cha racters of these two systems and discusses two urgent and important practi cal problems that the national gravity reference system is faced with in its performance: 1) the evaluation of the precision of the old system and the trans formation of this system into the new one; 2) the data-processing method for various sorts of high-precision additional gravity measurement controlled by the new net, e. g., the Grade J National Gravity Net.