Thousands of decimetric spikes were observed with a new spectrometer of Yunnan Observatory on June 24, 2001. The statistical analyses of the bandwidth, polarization degree, and half power duration of these spikes were made. We found that the absolute bandwidth of the spikes is down to the low limit of the instrument's spectral resolution (about 1.4 MHz). 76% of the total spikes have the polarization degree greater than 70%. The distribution of the half power durations concentrates on less than 16 milliseconds. These results support the interpretation of the electron cyclotron maser (ECM) mechanism for the decimetric spikes.