In September 2015, four dual-polarized weather radars of X-band were set up and conducted the observation test in Beijing area by Beijing Meteorological Bureau. Based on the observation data of the three radars on 30 June 2016, the observation parameters of radars have been conducted initial quality assessment by using the statistical method of standard deviation distribution. The results are as follows: (1) The 73.5%-77.9% of the total observation data of the reflectivity from the three radars conformed to the theoretical standard deviation distribution. It suggested that the fluctuation of the reflectivity data basically conformed to the theoretical distribution. (2) The 68.4%-81.4% of the total observation data of the differential reflectivity conformed to the theoretical standard deviation distribution. The fluctuation of data from Fangshan radar was the largest among the three radars. (3) For the cross correlation coefficient among the three radars, 45.7%-63.5% of the standard deviations conformed to the theory value. The data from Fangshan radar fluctuated most while data from the rest two radars showed the same scale of fluctuation. (4) For the standard deviations of differential-phase, 73.5%-83.9% of the data showed consistency with theoretical data. The fluctuation of data from Fangshan radar was relatively large. Compared with the other three observation parameters of radars, the variation of differential-phase was relatively small.